TECHNOLOGY FOCUS - ELECTRONICS - Preferred Components: The organoselenium material comprises organoselenium compounds (A). The organoselenium material is a host material, where the organic layer further comprises a dopant material. The organic layer is an emissive layer, where the dopant material is a phosphorescent or fluorescent dopant material. The dopant material is a phosphorescent dopant material comprising 29 iridium complexes of formulae (1a)-(10a), osmium complexes e.g. of formula (11a)-(13a), gold complexes of formula (14a) or (Cl-Au-P(phenyl)2-CH2-P(phenyl)2-Au-Cl), a rhenium complex of formula (15a), a ruthenium complex of formula (16a) or 6 platinum complexes of formula (17a)-(19a).    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation: No preparation method is given. SPECIFIC COMPOUNDS - 85 Compounds (A) are specifically claimed e.g. 4-(3-triphenylen-2-yl-phenyl)-dibenzoselenophene of formula (Aa), 2-triphenylen-2-yl-benzo(b)selenophene, 2-(3-triphenylen-2-yl-phenyl)-benzo(b)selenophene, 2,3-diphenyl-5-(3-triphenylen-2-yl-phenyl)-benzo(b)selenophene and 4-(3-(3-dibenzoselenophen-4-ylphenyl)phenyl)dibenzoselenophene.    EXAMPLE - Dibenzoselenophene (4 g) and dry ether (150 ml) were added in flask under nitrogen. To the mixture, butyl lithium (1.6 M in hexane, 11.5 ml) was added slowly. The reaction mixture was then heated to reflux for 5 hours. The reaction mixture was cooled to -78 degrees C and trimethyl borate (5 ml) was added. It was then left to stir for overnight. 1 M Hydrochloric acid (50 ml) was added to the reaction mixture and worked up to give dibenzoselenophen-4-ylboronic acid. Dibenzoselenophen-4-ylboronic acid (1 g), triphenylenephenyl triflate (1.51 g), tris(dibenzylideneacetone)dipalladium (0) (0.15 g), dicyclohexylphosphino-2',6'-dimethoxybiphenyl (0.27 g), potassium phosphate (4.2 g), toluene (90 ml) and water (10 ml) were added in a flask. The reaction mixture was bubbled with nitrogen for 20 minutes and heated to reflux for overnight under nitrogen. The reaction mixture was dried and purified to give 4-(3-triphenylen-2-yl-phenyl)-dibenzoselenophene (1.35 g).