TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Claimed): Preparation of (A) comprises: preparing a substituted carbazole derivative optionally under the introduction of halo substituents; coupling the nitrogen atoms of the carbazole derivatives in a metal organic coupling or a nucleophilic aromatic substitution reaction with a (hetero)aryl group; and metal organic coupling reaction for the introduction of (hetero)aryl groups to one or two aromatic six-membered rings of carbazole groups. SPECIFIC COMPOUNDS - 178 Compounds (I) are disclosed e.g. 3,3''-bis(4,6-diphenyl-(1,3,5)triazin-2-yl)-9,3':6',9''-ter-9H-carbazole of formula (Aa), 3-(6-(4,6-diphenyl-(1,3,5)triazin-2-yl)-dibenzothiophen-3-yl)-9-phenyl-9H-carbazole, 9-(4-(4,6-diphenyl-(1,3,5)triazin-2-yl)-2,6-dimethyl-phenyl)-2,7-bis-(4-(2-phenyl-carbazol-9-yl)-phenyl)-9H-carbazole, 7-(4-(3,6-dimethyl-carbazol-9-yl)-phenyl)-9-(4-(4,6-diphenyl-(1,3,5)triazin-2-yl)-2,6-dimethyl-phenyl)-3',6'-dimethyl-9H-(2,9')bicarbazolyl and 9'-(4-(4,6-di-p-tolyl-(1,3,5)triazin-2-yl)-phenyl)-3,6-diphenyl-9'H-(9,2';7',9'')tercarbazole.    EXAMPLE - A well stirred suspension of 2-phenylcarbazole (234 mmole), 3,6-dibromo-9-(phenylsulfonyl)-9H-carbazole (117 mmole) and potassium phosphate (1961 mmole) in dioxane (1170 ml) was mixed with copper(I) iodide (42.2 mmole) and trans-cyclohexanediamine (97.5 mmole) and then heated for 16 hours under reflux. After cooling, the precipitated solid was worked up to give 3,3''-bis(phenyl)-9'-((phenyl)sulfonyl)-9,3';6',9''-ter-9H-carbazole. 3,3''-Bis(phenyl)-9'-((phenyl)sulfonyl)-9,3':6',9''-tert-9H-carbazole (123 mmole) and potassium hydroxide (856 mmole) in dimethyl sulfoxide (65 ml) and water (21 ml) were heated for 1 hour under reflux. Then the reaction mixture was cooled to room temperature and neutralized with 1 M hydrochloric acid solution. Then the obtained product was extracted with dichloromethane, and worked up to give 3,3''-bis(phenyl)-9,3':6',9''-ter-9H-carbazole. Sodium hydride (40 mmole, 60% in oil) was added in dimethylformamide (150 ml). The obtained solution was added dropwise to a solution of 3,3''-bis(phenyl)-9,3':6',9''-ter-9H-carbazole (30 mmole) in dimethylformamide (50 ml). After 1 hour, 2-chloro-4,6-diphenyl-(1,3,5)-triazine (33 mmole) was added and stirred for 8 hours at room temperature. The precipitated solid was worked up to give 3,3''-bis(4,6-diphenyl-(1,3,5)triazin-2-yl)-9,3':6',9''-ter-9H-carbazole (yield 17.8 g (66%) and purity 99.9%).