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 containing a fluorescent material and having high emission efficiency is provided. The light-emitting element contains the fluorescent material and a host material. The host material contains a first organic compound and a second organic compound. The first organic compound and the second organic compound can form an exciplex. The proportion of a delayed fluorescence component in light emitted from the exciplex is higher than or equal to 5%, and the delayed fluorescence component contains a delayed fluorescence component whose fluorescence lifetime is 10 ns or longer and 50 ?s or shorter.

Abstract: A light-emitting element containing a fluorescent material and having high emission efficiency is provided. The light-emitting element contains the fluorescent material and a host material. The host material contains a first organic compound and a second organic compound. The first organic compound and the second organic compound can form an exciplex. The minimum value of a distance between centroids of the fluorescent material and at least one of the first organic compound and the second organic compound is 0.7 nm or more and 5 nm or less.

Abstract: The organic compound represented by Formula G1 below has a structure in which the 2-position of a dibenzoquinazoline ring is directly, or via one or more arylene groups, bonded to a skeleton with a hole-transport property. In the formula, n represents any of 0 to 3, m represents 1 or 2, A represents a single bond, or a substituted or unsubstituted arylene group having 6 to 13 carbon atoms, B represents a ring having a substituted or unsubstituted dibenzofuran skeleton, a substituted or unsubstituted dibenzothiophene skeleton, or a substituted or unsubstituted carbazole skeleton, and 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 7 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms.

Abstract: To provide an organometallic complex with high emission efficiency and high heat resistance, which emits yellow green light. The organometallic complex includes a metal and a ligand which is a benzo[h]quinazoline skeleton including a condensed ring bonded to benzo[h]quinazoline through a carbon-carbon bond between the 5-position and the 6-position. The organometallic complex has a structure represented by General Formula (G1). In General Formula (G1), M represents a metal belonging to Group 9 or 10; each of R1 to R4 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; and R5 represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted phenyl group. A ring X represents a substituted or unsubstituted six-membered aromatic ring formed with carbon or both carbon and nitrogen.

Abstract: To provide a light-emitting element which uses a fluorescent material as a light-emitting substance and has higher luminous efficiency. To provide a light-emitting element which includes a mixture of a thermally activated delayed fluorescent substance and a fluorescent material. By making the emission spectrum of the thermally activated delayed fluorescent substance overlap with an absorption band on the longest wavelength side in absorption by the fluorescent material in an S1 level of the fluorescent material, energy at an S1 level of the thermally activated delayed fluorescent substance can be transferred to the S1 of the fluorescent material. Alternatively, it is also possible that the Si of the thermally activated delayed fluorescent substance is generated from part of the energy of a T1 level of the thermally activated delayed fluorescent substance, and is transferred to the S1 of the fluorescent material.

Abstract: To provide a novel heterocyclic compound capable of being used as a host material in which a light-emitting substance is dispersed. To provide a light-emitting element having a long lifetime. A heterocyclic compound in which a dibenzo[f,h]quinoxalinyl group and a benzo[b]naphtho[1,2-d]furanyl group are bonded through an arylene group having 6 to 13 carbon atoms. The dibenzo[f,h]quinoxalinyl group, the benzo[b]naphtho[1,2-d]furanyl group, and the arylene group separately are unsubstituted or have, as a substituent, an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 13 carbon atoms.

Abstract: A novel organic compound is provided. In addition, a novel organic compound with high heat resistance is provided. In the organic compound, a dibenzoquinoxaline skeleton and a 4,4-bidibenzofuran skeleton or a 4,4?-bidibezothiophene skeleton are connected to each other through an arylene group.

Abstract: Provided as a novel substance is a long-lifetime organometallic iridium complex emitting yellow light with high emission efficiency. The organometallic iridium complex is represented by General Formula (G1) and has a structure in which a phenyl group whose 2-position and 6-position are each substituted by an alkyl group is bonded to the 4-position of pyrimidine. In General Formula (G1), R1 and R2 each independently represent a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms.

Abstract: To provide a light-emitting element which uses a fluorescent material as a light-emitting substance and has higher luminous efficiency. To provide a light-emitting element which includes a mixture of a thermally activated delayed fluorescent substance and a fluorescent material. By making the emission spectrum of the thermally activated delayed fluorescent substance overlap with an absorption band on the longest wavelength side in absorption by the fluorescent material in an S1 level of the fluorescent material, energy at an S1 level of the thermally activated delayed fluorescent substance can be transferred to the S1 of the fluorescent material. Alternatively, it is also possible that the S1 of the thermally activated delayed fluorescent substance is generated from part of the energy of a T1 level of the thermally activated delayed fluorescent substance, and is transferred to the S1 of the fluorescent material.

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: A light-emitting element with high emission efficiency is provided. In addition, a light-emitting element having a low driving voltage is provided. Furthermore, a novel compound which can be used for a transport layer, a host material, or a light-emitting material of a light-emitting element is provided. A novel compound including a benzothienopyrimidine skeleton is provided. Furthermore, a light-emitting element including a pair of electrodes and an EL layer sandwiched between the pair of electrodes is provided. The EL layer contains a substance including the benzothienopyrimidine skeleton.

Abstract: Provided is a novel heterocyclic compound, a novel heterocyclic compound that can be used in a light-emitting element, or a highly reliable light-emitting device, electronic device, and lighting device in each of which the light-emitting element using the novel heterocyclic compound is used. One embodiment of the present invention is a heterocyclic compound represented by General Formula (G1). In General Formula (G1), each of A1 and A2 independently represents nitrogen or carbon bonded to hydrogen, and at least one of A1 and A2 represents nitrogen; Ar represents a substituted or unsubstituted arylene group having 6 to 18 carbon atoms; B represents a substituted or unsubstituted fluorenyl group; and R1 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms.

Abstract: To provide a novel compound which can be used as a host material in which a light-emitting substance is dispersed. To provide a light-emitting element having a long lifetime. A compound represented by General Formula (G0). In the formula, A1 represents a dibenzo[f,h]quinoxalinyl group, A2 represents a benzo[b]naphtho[2,3-d]furanyl group, and Ar represents an arylene group having 6 to carbon atoms. The dibenzo[f,h]quinoxalinyl group, the benzo[b]naphtho[2,3-d]furanyl group, and the arylene group are separately unsubstituted or substituted by any one of an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 13 carbon atoms.

Abstract: To provide a novel compound which can be used as a host material in which a light-emitting substance is dispersed. To provide a light-emitting element having a long lifetime. A compound represented by General Formula (G0). In the formula, A represents any one of a substituted or unsubstituted dibenzothiophenylene group and a substituted or unsubstituted dibenzofuranylene group, X represents a substituted or unsubstituted fluorenyl group, E represents a substituted or unsubstituted dibenzo[f,h]quinoxalinyl group, and Ar represents a substituted or unsubstituted arylene group having 6 to 30 carbon atoms.

Abstract: A novel heterocyclic compound is provided. A novel heterocyclic compound that can be used for a light-emitting element is provided. A novel heterocyclic compound that can improve the reliability of a light-emitting element when used for a light-emitting element is provided. A light-emitting element, a light-emitting device, an electronic appliance, or a lighting device which includes the novel heterocyclic compound and is highly reliable is provided. One embodiment of the present invention is a heterocyclic compound represented by a general formula (G0). In the general formula (G0), A represents a dibenzo[f,h]quinoxalinyl group, B represents a substituted or unsubstituted fluorenyl group, and Ar represents a substituted or unsubstituted arylene group having 6 to 25 carbon atoms.

Abstract: A multicolor light-emitting element using fluorescence and phosphorescence, which has a small number of manufacturing steps owing to a relatively small number of layers to be formed and is advantageous for practical application can be provided. In addition, a multicolor light-emitting element using fluorescence and phosphorescence, which has favorable emission efficiency is provided. A light-emitting element which includes a light-emitting layer having a stacked-layer structure of a first light-emitting layer exhibiting light emission from a first exciplex and a second light-emitting layer exhibiting phosphorescence is provided.

Abstract: A light-emitting element with high emission efficiency is provided. A light-emitting element with a long lifetime is provided. The light-emitting element includes an anode; a hole-transport layer over the anode, containing a hole-transport compound and a compound; a light-emitting layer over the hole-transport layer, containing a host material and a guest material; and a cathode over the light-emitting layer. The host material is an electron-transport compound. The guest material and the compound are each independently a phosphorescent compound or a thermally activated delayed fluorescence material. A peak of an emission spectrum of the compound is on a shorter wavelength side than a peak of an emission spectrum of the guest material. Only the guest material emits light.

Abstract: A multicolor light-emitting element using fluorescence and phosphorescence, which has a small number of manufacturing steps owing to a relatively small number of layers to be formed and is advantageous for practical application can be provided. In addition, a multicolor light-emitting element using fluorescence and phosphorescence, which has favorable emission efficiency is provided. A light-emitting element which includes a light-emitting layer having a stacked-layer structure of a first light-emitting layer exhibiting light emission from a first exciplex and a second light-emitting layer exhibiting phosphorescence is provided.

Abstract: Provided is a heterocyclic compound that can be used for a carrier-transport material, a host material, or a light-emitting material in a light-emitting element. The heterocyclic compound has an indolo[3,2,1-jk]carbazole skeleton and a dibenzo[f,h]quinoxaline skeleton which are linked to each other through an arylene group. The wide band gap of the heterocyclic compound allows excitation of a green-emissive phosphorescent material, which contributes to the formation of a highly efficient light-emitting element.