TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation: No preparation method is given. Preferred Components: The dopant is an organo-metallic iridium material. The host is a compound comprising a triphenylene containing benzo-fused thiophene, preferably 4-(3-triphenylen-2-yl-phenyl)-dibenzothiophene, or an aryltriphenylene compound, preferably 3,3'-di(triphenylen-2-yl)biphenyl. SPECIFIC COMPOUNDS - 18 Compounds (I) are specifically claimed, e.g. N4,N4,N4'-triphenyl-N4'-(3-triphenylen-2-yl-phenyl)-biphenyl-4,4'-diamine of formula (Ia), N4-biphenyl-4-yl-N4,N4'-diphenyl-N4'-(3-triphenylen-2-yl-phenyl)-biphenyl-4,4'-diamine, N4,N4-bis-biphenyl-4-yl-N4'-phenyl-N4'-(3-triphenylen-2-yl-phenyl)-biphenyl-4,4'-diamine, N4,N4'-diphenyl-N4-(1,1';4',1'')terphenyl-4-yl-N4'-(3-triphenylen-2-yl-phenyl)-biphenyl-4,4'-diamine and N4,N4'-diphenyl-N4,N4'-bis-(3-triphenylen-2-yl-phenyl)-biphenyl-4,4'-diamine.    EXAMPLE - 4-(Diphenylamino)phenylboronic acid (4.87 g), 4-bromo-N-phenylaniline (3.5 g), potassium phosphate (9.2 g), dicyclohexyl(2',6'-dimethoxybiphenyl- 2-yl)phosphine (0.23 g) were added to a flask under nitrogen. Toluene (200 ml) and water (20 ml) were then added. The solution was degassed with nitrogen for 20 minutes. Tris(dibenzylideneacetone)dipalladium(0) (0.13 g) was added to the mixture. The mixture was then heated up to reflux overnight. After cooled to room temperature, the organic layer was separated and dried over magnesium sulfate and worked up to give N4, N4, N4'-triphenylbiphenyl-4,4'-diamine (4.7 g, 81%). Tris(dibenzylideneacetone)dipalladium(0) (0.07 g) and dicyclohexyl(2',6'-dimethoxybiphenyl-2-yl)phosphine (0.13 g) were added to a flask under nitrogen. Xylene (150 ml) was then added. The solution was stirred under nitrogen for 20 minutes. To the solution 3-(triphenylen-2-yl)phenyl trifluoromethanesulfonate (3.87 g), sodium tert-butoxide (1.1 g), and N4,N4,N4'-triphenylbiphenyl-4,4'-diamine (3.2 g) were added in sequence. The mixture was then heated up to reflux overnight. After cooled to room temperature, dichloromethane (300 ml) was added to the solution and worked up to give N4, N4, N4'-triphenyl-N4'-(3-triphenylen-2-yl-phenyl)-biphenyl-4,4'-diamine (3.5 g, 64%).