Abstract: Provided are organometallic complexes that can exhibit phosphorescence. One of the novel organometallic complexes is represented by General Formula (G1). In General Formula (G1), R1 represents any of an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms which may have a substituent, and an aralkyl group having 7 to 10 carbon atoms which may have a substituent. In addition, R2 represents any of an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms which may have a substituent, and an aryl group having 6 to 12 carbon atoms which may have a substituent. Further, Ar represents an arylene group having 6 to 13 carbon atoms which may have a substituent. Further, M represents a Group 9 element or a Group 10 element.

Abstract: To provide a light-emitting element with an improved reliability, a light-emitting element with a high current efficiency (or a high quantum efficiency), and a novel dibenzo[f,h]quinoxaline derivative that is favorably used in a light-emitting element which is one embodiment of the present invention. A light-emitting element includes an EL layer between an anode and a cathode. The EL layer includes a light-emitting layer; the light-emitting layer contains a first organic compound having an electron-transport property and a hole-transport property, a second organic compound having a hole-transport property, and a light-emitting substance; the combination of the first organic compound and the second organic compound forms an exciplex; the HOMO level of the first organic compound is lower than the HOMO level of the second organic compound; and a difference between the HOMO level of the first organic compound and the HOMO level of the second organic compound is less than or equal to 0.4 eV.

Abstract: Provided is a light-emitting element with high external quantum efficiency, or a light-emitting element with a long lifetime. The light-emitting element includes, between a pair of electrodes, a light-emitting layer including a guest material and a host material, in which an emission spectrum of the host material overlaps with an absorption spectrum of the guest material, and phosphorescence is emitted by conversion of an excitation energy of the host material into an excitation energy of the guest material. By using the overlap between the emission spectrum of the host material and the absorption spectrum of the guest material, the energy smoothly transfers from the host material to the guest material, so that the energy transfer efficiency of the light-emitting element is high. Accordingly, a light-emitting element with high external quantum efficiency can be achieved.

Abstract: As a novel substance having a novel skeleton, an organometallic complex with high emission efficiency is provided. The organometallic complex includes a metal and a ligand. The metal is iridium or platinum. The ligand includes a 5H-pyrimido[5,4-b]indole skeleton and an aryl group bonded to the 4-position of the 5H-pyrimido[5,4-b]indole skeleton. The 3-position of the 5H-pyrimido[5,4-b]indole skeleton and the aryl group are bonded to the metal. In the formula, M represents iridium or platinum. In addition, Ar represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and each of R1 to R6 independently represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 10 carbon atoms.

Abstract: A light-emitting element having high external quantum efficiency is provided. A light-emitting element having low drive voltage is provided. Provided is a light-emitting element which includes a light-emitting layer containing a phosphorescent compound, a first organic compound, and a second organic compound between a pair of electrodes. A combination of the first organic compound and the second organic compound forms an exciplex (excited complex). An emission spectrum of the exciplex overlaps with an absorption band located on the longest wavelength side of an absorption spectrum of the phosphorescent compound. A peak wavelength of the emission spectrum of the exciplex is longer than or equal to a peak wavelength of the absorption band located on the longest wavelength side of the absorption spectrum of the phosphorescent compound.

Abstract: Provided is a novel compound or a light-emitting element with high emission efficiency. The provided novel compound includes a bicarbazole skeleton and a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton. The provided light-emitting element includes the compound.

Abstract: A novel organic compound that can be used as an electron-injection material or an electron-transport material of a light-emitting element is provided. An organic compound with which a display device having less crosstalk can be obtained is provided. A light-emitting device, a display device, and an electronic device each having less crosstalk are provided. An organic compound including two or three benzo[h]quinazoline rings is provided. In the organic compound, two or three benzo[h]quinazoline rings are preferably included in the substituent including an aromatic ring or a heteroaromatic ring and having 3 to 30 carbon atoms. When two or three benzo[h]quinazoline rings are included in a substituent particularly including a heteroaromatic ring and having 3 to 30 carbon atoms, a high electron-transport property can be obtained.

Abstract: Provided is a light-emitting element with high external quantum efficiency, or a light-emitting element with a long lifetime. The light-emitting element includes, between a pair of electrodes, a light-emitting layer including a guest material and a host material, in which an emission spectrum of the host material overlaps with an absorption spectrum of the guest material, and phosphorescence is emitted by conversion of an excitation energy of the host material into an excitation energy of the guest material. By using the overlap between the emission spectrum of the host material and the absorption spectrum of the guest material, the energy smoothly transfers from the host material to the guest material, so that the energy transfer efficiency of the light-emitting element is high. Accordingly, a light-emitting element with high external quantum efficiency can be achieved.

Abstract: An organometallic iridium complex having high emission efficiency and high heat resistance and emitting yellow light is provided as a novel substance. The organometallic iridium complex includes iridium and a ligand and includes a structure represented by General Formula (G1). The ligand includes a 5H-indeno[1,2-d]pyrimidine skeleton and an aryl group bonded to the 4-position of the 5H-indeno[1,2-d]pyrimidine skeleton. The 3-position of the 5H-indeno[1,2-d]pyrimidine skeleton and the aryl group are bonded to the iridium. In the formula, Ar represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and each of R1 to R7 independently represents hydrogen or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms.

Abstract: A light-emitting element having high external quantum efficiency is provided. A light-emitting element having low drive voltage is provided. Provided is a light-emitting element which includes a light-emitting layer containing a phosphorescent compound, a first organic compound, and a second organic compound between a pair of electrodes. A combination of the first organic compound and the second organic compound forms an exciplex (excited complex). An emission spectrum of the exciplex overlaps with an absorption band located on the longest wavelength side of an absorption spectrum of the phosphorescent compound. A peak wavelength of the emission spectrum of the exciplex is longer than or equal to a peak wavelength of the absorption band located on the longest wavelength side of the absorption spectrum of the phosphorescent compound.

Abstract: A light-emitting element having high emission efficiency is provided. A light-emitting element having a low driving voltage is provided. A novel compound which can be used for a transport layer or as a host material or a light-emitting material of a light-emitting element is provided. A novel compound with a benzofuropyrimidine skeleton is provided. Also provided is a light-emitting element which includes the compound with the benzofuropyrimidine skeleton between a pair of electrodes.

Abstract: A light-emitting element having high external quantum efficiency is provided. A light-emitting element having a long lifetime is provided. A light-emitting element is provided which includes a light-emitting layer containing a phosphorescent compound, a first organic compound, and a second organic compound between a pair of electrodes, in which a combination of the first organic compound and the second organic compound forms an exciplex (excited complex). The light-emitting element transfers energy by utilizing an overlap between the emission spectrum of the exciplex and the absorption spectrum of the phosphorescent compound and thus has high energy transfer efficiency. Therefore, a light-emitting element having high external quantum efficiency can be obtained.

Abstract: A novel organometallic complex having high heat resistance is provided. The organometallic complex, which includes a structure represented by General Formula (G1), includes iridium and a ligand. The ligand has a pyrazine skeleton. Iridium is bonded to nitrogen at the 1-position of the pyrazine skeleton. A phenyl group that has an alkyl group as a substituent is bonded at each of the 2- and 3-positions of the pyrazine skeleton, and a phenyl group that has a cyano group as a substituent is bonded at the 5-position of the pyrazine skeleton. The ortho position of the phenyl group bonded at the 2-position of the pyrazine skeleton is bonded to iridium. In the formula, each of A1 to A4 independently represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms.

Abstract: A novel organometallic complex having high reliability is provided. The organometallic complex includes platinum and a ligand coordinated to the platinum. The ligand includes a plurality of pyridoindole skeletons. Each of the pyridoindole skeletons includes nitrogen bonded to the platinum. Each of the pyridoindole skeletons is bonded to an arylene group bonded to the platinum.

Abstract: An object is to provide a novel organometallic complex. Another object is to provide an organometallic complex that can exhibit yellow to blue phosphorescence. A platinum complex with a tetracoordinate ligand including a phenothiazine skeleton or a phenoxazine skeleton is provided. In the ligand, nitrogen at the 10-position and carbon at the 2-position of the phenothiazine skeleton or the phenoxazine skeleton have a pyridyl group and a phenoxy group, respectively. A five-membered heteroaromatic residue is present at the 3-position of the phenoxy group. The five-membered heteroaromatic residue has two or three nitrogen atoms in its skeleton. Carbon at the 1-position of the phenothiazine skeleton or the phenoxazine skeleton and carbon at the 2-position of the phenoxy group are bonded to platinum, and nitrogen of the pyridyl group and nitrogen or carbene carbon of the five-membered heteroaromatic residue are coordinated to platinum.

Abstract: Provided is a novel compound or a light-emitting element with high emission efficiency. The provided novel compound includes a bicarbazole skeleton and a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton. The provided light-emitting element includes the compound.

Abstract: Light-emitting elements having high emission efficiency and long lifetime can be provided. By forming light-emitting devices including the light-emitting elements, the light-emitting devices having low power consumption and long lifetime can be provided. A light-emitting device comprises a light-emitting element including a light-emitting layer between a first electrode and a second electrode. The light-emitting layer includes a first organic compound having a hole-transporting property, a second organic compound having an electron transporting property, and an organometallic complex. A central metal of the organometallic complex is an element belonging to one of Group 9 and Group 10, and a ligand of the organometallic complex is a ligand having a pyrazine skeleton.

Abstract: A high-purity organometallic iridium complex is provided. The organometallic iridium complex includes iridium and a plurality of ligands cyclometallated to the iridium. Each of the plurality of ligands includes a heteroaromatic ring having a coordinatable nitrogen atom. In LC analysis of the organometallic iridium complex, an impurity which has a monochlorinated ligand among the plurality of ligands is 0.1% or less by quantitating using peak area count with a PDA detector.

Abstract: A light-emitting element having high emission efficiency is provided. A light-emitting element having a low driving voltage is provided. A novel compound which can be used for a transport layer or as a host material or a light-emitting material of a light-emitting element is provided. A novel compound with a benzofuropyrimidine skeleton is provided. Also provided is a light-emitting element which includes the compound with the benzofuropyrimidine skeleton between a pair of electrodes.

Abstract: Provided is an organometallic complex which emits light with a short wavelength and has high emission efficiency and high heat resistance. The organometallic complex includes a central metal; and a first ligand, a second ligand, a third ligand, and a fourth ligand which are coordinated to the central metal. The first ligand includes a triazole skeleton including nitrogen bonded to the central metal. The second ligand includes an indolo[3,2-b]carbazole skeleton whose 6-position is bonded to the central metal or a pyrido[2,3-b:6,5-b?]diindole skeleton whose 6-position is bonded to the central metal. The third ligand includes a benzene skeleton whose carbon is bonded to the central metal. The fourth ligand includes a pyridine skeleton whose nitrogen is bonded to the central metal or a benzene skeleton whose carbon is bonded to the central metal.