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 novel organometallic complex is provided. An organometallic complex emitting green to blue phosphorescence is provided. An organometallic complex having a deep LUMO level and emitting green to blue phosphorescence is provided. A light-emitting element with high emission efficiency is provided. A light-emitting element emitting green to blue phosphorescence and having low drive voltage is provided. A light-emitting device with low power consumption is provided. The organometallic complex includes iridium and a ligand having a triazole skeleton. The triazole skeleton has a group including a pyridine ring or a group including a pyrimidine ring and an aryl group. One of nitrogen atoms included in the triazole skeleton is coordinated to the iridium. The aryl group is bonded to the iridium at the ortho position of the aryl group.

Abstract: A tris-type iridium complex in which a ligand having a distinctive nitrogen-containing five-membered heterocyclic skeleton is coordinated is provided. The ligand has a nitrogen-containing five-membered heterocyclic skeleton composed of 2 to 4 nitrogen atoms and one or more carbon atoms. In the skeleton, an aryl group is bonded to a carbon atom on both sides of which nitrogen atoms are positioned, and a tricycloalkyl group having a bridge structure and having 9 or 10 carbon atoms is bonded to one of the two nitrogen atoms positioned on both the sides of the carbon atom. The tricycloalkyl group having a bridge structure and having 9 or 10 carbon atoms may be an adamantyl group or a noradamantyl group.

Abstract: An organometallic complex which can be provided at low cost and which emits blue phosphorescence is provided. An organometallic complex in which nitrogen at the 1-position of a 5-aryl-4H-1,2,4-triazole derivative is coordinated to a Group 9 metal or a Group 10 metal, the aryl group is bonded to the Group 9 metal or the Group 10 metal, and the 5-aryl-4H-1,2,4-triazole derivative is a 3-aryl-5,6,7,8-tetrahydro-4H-[1,2,4]triazolo[4,3-a]pyridine derivative is provided. The organometallic complex emits green to blue phosphorescence and is also advantageous in terms of cost.

Abstract: A novel organometallic complex having a low HOMO level and emitting blue to green phosphorescence is provided. The organometallic complex includes a structure represented by General Formula (G1). The organometallic complex includes iridium and a ligand. The ligand has an imidazole skeleton including nitrogen bonded to the iridium, and an N-carbazolyl group bonded to the 2-position of the imidazole skeleton through a phenylene group. The phenylene group is bonded to the iridium. In the formula, each of R1 to R14 independently represents any of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 5 to 8 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms.

Abstract: A novel organometallic complex which can emit phosphorescence is provided. A light-emitting element, a light-emitting device, an electronic device, or a lighting device with high emission efficiency is provided. The organometallic complex having an aryl triazine derivative as a ligand is represented by General Formula (G1) below as a representative of the organometallic complex of the present invention.

Abstract: A composition comprising a dibenzo[f,h]quinoxaline derivative in which impurities are reduced and a method of synthesizing dibenzo[f,h]quinoxaline in which impurities are reduced are provided. In addition, a light-emitting element, a light-emitting device, an electronic appliance, or a lighting device with high emission efficiency and high reliability in which dibenzo[f,h]quinoxaline is used as an EL material is provided. In the synthesis method, 2-(chloroaryl)dibenzo[f,h]quinoxaline is used as a synthetic intermediate in a synthetic pathway so that an impurity contained in a final product can be removed easily by purification by sublimation.

Abstract: A novel light-emitting material is provided. A novel orgnometallic complex is provided. An orgnometallic complex having a high carrier-transport property is provided. An orgnometallic complex having a deep HOMO level and/or a deep LUMO level is provided. An orgnometallic complex having a high charge-injection property is provided. Another object is to provide an organometallic complex that can exhibit yellow to blue phosphorescence. An organometallic complex that has a high carrier-transport property and exhibits green to blue phosphorescence is provided. An organometallic complex including a ligand having a structure of 5-(2-pyridinyl)-5H-benzimidazo[1,2-a]benzimidazole and a light-emitting material including the organometallic complex are provided.

Abstract: A compound includes a benzofuropyrimidine skeleton or a benzothienopyrimidine skeleton, a first substituent, and a second substituent. Each of the first substituent and the second substituent includes a furan skeleton, a thiophene skeleton, or a pyrrole skeleton. The first substituent is bonded to a pyrimidine ring included in the benzofuropyrimidine skeleton or a pyrimidine ring included in the benzothienopyrimidine skeleton. The second substituent is bonded to a benzene ring included in the benzofuropyrimidine skeleton or a benzene ring included in the benzothienopyrimidine skeleton. The light-emitting element includes the compound.

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: To provide a novel organometallic complex having high color purity. The organometallic complex is represented by General Formula (G1), and includes iridium and a ligand. The ligand includes a five-membered aromatic heterocycle including two or more nitrogen atoms and a plurality of aryl groups bonded to the five-membered aromatic heterocycle. At least one of the plurality of aryl groups includes a pentafluorosulfanyl group as a substituent.

Abstract: The light emitting element includes a first electrode and a second electrode, between which a light emitting layer, a hole transporting layer provide in contact with the light emitting layer, an electron transporting layer provided in contact with the light emitting layer, and a mixed layer provided between the electron transporting layer and the second electrode. The mixed layer includes an electron transporting substance and a substance showing an electron donating property with respect to the electron transporting substance. The light emitting layer includes an organometallic complex represented in General Formula (1) and a host. R1 and R2 each represent an electron-withdrawing substituent group. R3 and R4 each represent any of hydrogen or an alkyl group having 1 to 4 carbon atoms. L represents any of a monoanionic ligand having a beta-diketone structure, a monoanionic bidentate chelating ligand having a carboxyl group, or a monoanionic bidentate chelating ligand having a phenolic hydroxyl group.

Abstract: A novel organometallic complex having high color purity is provided. The organometallic complex includes a structure which includes iridium and a ligand and is represented by a general formula (G1). The ligand includes a pyrido[2,3-b]indole skeleton and a pyrimidine skeleton bonded to the 3-position of the pyrido[2,3-b]indole skeleton. The 2-position of the pyrido[2,3-b]indole skeleton and the pyrimidine skeleton are each bonded to the iridium. In the general formula (G1), R1 to R9 each independently represent any of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 12 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 novel organometallic complex which can emit phosphorescence is provided. A light-emitting element, a light-emitting device, an electronic device, or a lighting device with high emission efficiency is provided. The organometallic complex having an aryl triazine derivative as a ligand is represented by General Formula (G1) below as a representative of the organometallic complex of the present invention.

Abstract: As a novel substance having a novel skeleton, an organometallic complex with high emission efficiency which achieves improved color purity by a reduction of half width of an emission spectrum is provided. One embodiment of the present invention is an organometallic complex in which a ?-diketone and a six-membered heteroaromatic ring including two or more nitrogen atoms inclusive of a nitrogen atom that is a coordinating atom are ligands. In General Formula (G1), X represents a substituted or unsubstituted six-membered heteroaromatic ring including two or more nitrogen atoms inclusive of a nitrogen atom that is a coordinating atom. Further, R1 to R4 each represent a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms.

Abstract: A novel organometallic complex with high reliability is provided. The organometallic complex includes iridium and ligands coordinated to the iridium. The ligands are a dipivaloylmethanato ligand and a ligand including a phenyl group to which an alkyl group is bonded and which is bonded to the 5-position of a pyrazine ring. In the formula, Ar represents a substituted or unsubstituted arylene group having 6 to 13 carbon atoms; and R1 and R2 each independently represent a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms. R3 to R6 each independently represent any of hydrogen, halogen, a cyano group, a substituted or unsubstituted amino group, a substituted or unsubstituted hydroxyl group, a substituted or unsubstituted mercapto group, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms.

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: 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.