TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The organic light-emitting diode comprises an anode and a cathode and at least one light-emitting layer arranged between the anode and the cathode, and optionally at least one further layer comprising at least one blocking layer for holes/excitons, at least one blocking layer for electrons/excitons, at least one hole injection layer, at least one hole conductor layer, at least one electron injection layer or at least one electron conductor layer, where (I) or (III) is present in the electron conductor layer and/or light-emitting layer and/or in at least one of the further layers.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: (I) is not 2,8-bis(2,5-dimethyl-1H-pyrrol-1-yl)dibenzo(b,d)thiophene. (I) is substituted 2-phenyl-1H-imidazole compounds of formula (IA) or substituted (1,1';3',1'')terphenyl compounds of formula (IB). The organic light-emitting diode is electron transport material. The organic light-emitting diode comprises at least one (I) as host, blocker and/or charge transport material. The material, (III) or (I) is used as matrix material, hole/exciton blocker material, electron/exciton blocker material, hole injection material, electron injection material, hole conductor material, electron conductor material, hole conductor and/or electron conductor. At least one of (III) or (I) is present in the electron conductor layer, the light-emitting layer and/or the blocking layer for holes/excitons. The material is present in the electron conductor layer, the light-emitting layer and/or in the blocking layer for holes/excitons. Preferred Definitions:    R1 = phenyl, naphthyl, anthracenyl, phenanthrenyl, indanyl, fluorenyl, pyridinyl, pyrimidinyl, pyrrolyl, furanyl, pyrazolyl, imidazolyl, thiophenyl, oxazolyl, thiazolyl, triazolyl, benzofuryl, benzothienyl, benzopyrrolyl, dibenzofuryl, phenanthrolinyl, carbazolyl, azacarbazolyl or diazacarbazoyl (all optionally substituted), alkyl, cycloalkyl, heterocycloalkyl, crosslinkable or polymerizable group bonded via a spacer, -NR3R4, -P(O)R5R6, -PR7R8, -S(O)2R9, -S(O)R10, -SR11 or -OR12;    n = 1;    m = 0;    X = O; and    Z = substituted 4H-(1,2,4)triazole moiety of formula (a1), substituted 2H-(1,2,3)triazole moiety of formula (a2), substituted 1H-(1,2,3)triazole moiety of formula (a3) or substituted 1H-(1,2,4)triazole moiety of formula (a4), where R1a is not carbazol-9-yl.    SPECIFIC COMPOUNDS - 50 Compounds (I) are specifically claimed e.g. 2,8-bis(2-phenyl-1H-benzo(d)imidazol-1-yl)dibenzo(b,d)thiophene of formula (Ia), 2,8-bis(2-phenyl-1H-benzo(d)imidazol-1-yl)dibenzo(b,d)furan, 2,8-bis(2-phenyl-1H-imidazol-1-yl)dibenzo(b,d)furan, 2,8-bis(2-phenyl-1H-imidazol-1-yl)dibenzo(b,d)thiophene and 4-(dibenzo(b,d)thiophen-2-yl)-3,5-diphenyl-4H-1,2,4-triazole. 20 Compounds (III) are specifically claimed e.g. 2-carbazolyl-8-(2-phenylbenzimidazol-1-yl)dibenzofuran of formula (IIIa), 9-(8-(2-phenyl-imidazol-1-yl)-dibenzofuran-2-yl)-9H-carbazole, 9-(8-(2-phenyl-imidazol-1-yl)-dibenzothiophen-2-yl)-9H-carbazole, 9-(3-(1-(8-(9H-carbazol-9-yl)dibenzo(b,d)thiophen-2-yl)-1H-imidazol-2-yl)phenyl)-9H-carbazole and 9-(3-(1-(8-(9H-carbazol-9-yl)dibenzo(b,d)furan-2-yl)-1H-imidazol-2-yl)phenyl)-9H-carbazole.    EXAMPLE - 2-Carbazolyl-8-benzimidazol-1-yldibenzofuran (2.25 g) was combined with palladium acetate (56 mg), copper iodide (1.93 g) and iodobenzene (2.08 g) in dimethylformamide (30 ml) under argon. The reaction mixture was degassed with argon and heated to 140 degrees C and stirred for 24 hours. Then the reaction mixture was cooled and ethyl acetate (300 ml) was added. The resultant suspension was filtered and washed with ethyl acetate (2 l). The reaction solution was concentrated, and obtained residue was extracted by stirring in ethyl acetate (200 ml). The suspension was filtered, concentrated and filtered with suction. The solid was washed with a little ethyl acetate and then purified to obtain 2-carbazolyl-8-(2-phenylbenzimidazol-1-yl)dibenzofuran (1.43 g).