TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preparation (Disclosed): Iridium trichloride hydrate is reacted with excess of dibenzo(f,h)quinoxaline compound of formula: La'H in presence of silver trifluoroacetate and optionally in presence of a solvent, to obtain tris-cyclometalated iridium complex of formula: Ir(La')3. Preferred Composition: The emitting layer further contains a host material. SPECIFIC COMPOUNDS - 389 Metal complexes are specifically claimed e.g. 19-((2R)-4,6-dimethyl-2H-1,3-dioxin-2-yl)-8,8',15,15'-tetramethyl-1,1',4,4'-tetraaza-19-irida-19,19'-spirobi(pentacyclo(14.2.1.05,18.06,11.012,17)nonadecan)-1,1',3,3',5(18),5'(18'),6(11),6'(11'),7,7',9,9',12,12',14,14',16,16'-octadecaene of formula (Ia), 19-((2R)-4,6-dimethyl-2H-1,3-dioxin-2-yl)-3,3',8,8',15,15'-hexamethyl-1,1',4,4'-tetraaza-19-irida-19,19'-spirobi(pentacyclo(14.2.1.05,18.06,11.012,17)nonadecan)-1,1',3,3',5(18),5'(18'),6(11),6'(11'),7,7',9,9',12,12',14,14',16,16'-octadecaene, 19-((2R)-4,6-dimethyl-2H-1,3-dioxin-2-yl)-3,3'-diethyl-8,8',15,15'-tetramethyl-1,1',4,4'-tetraaza-19-irida-19,19'-spirobi(pentacyclo(14.2.1.05,18.06,11.012,17)nonadecan)-1,1',3,3',5(18),5'(18'),6(11),6'(11'),7,7',9,9',12,12',14,14',16,16'-octadecaene, 19-((2R)-4,6-dimethyl-2H-1,3-dioxin-2-yl)-8,8',15,15'-tetramethyl-3,3'-dipropyl-1,1',4,4'-tetraaza-19-irida-19,19'-spirobi(pentacyclo(14.2.1.05,18.06,11.012,17)nonadecan)-1,1',3,3',5(18),5'(18'),6(11),6'(11'),7,7',9,9',12,12',14,14',16,16'-octadecaene and 3,3'-dibutyl-19-((2R)-4,6-dimethyl-2H-1,3-dioxin-2-yl)-8,8',15,15'-tetramethyl-1,1',4,4'-tetraaza-19-irida-19,19'-spirobi(pentacyclo(14.2.1.05,18.06,11.012,17)nonadecan)-1,1',3,3',5(18),5'(18'),6(11),6'(11'),7,7',9,9',12,12',14,14',16,16'-octadecaene.    EXAMPLE - 6.03 g 6,11-Dibromo-2-methyldibenzo(f,h)quinoxaline and 4.58 g (2-methylpropyl)boronic acid were suspended under argon in 200 ml toluene, 0.13 g palladium(II) acetate and 0.74 g 2-dicyclohexyl-phosphino-2',6'-dimethoxybiphenyl were added, 34.5 g potassium phosphate hydrate was added, reaction mixture was degassed with argon, obtained light yellow suspension was heated under reflux for three hours, resultant hot grey suspension was filtered through silica gel, rinsed with toluene, collected eluent was concentrated under vacuum and resulting solid was recrystallized from ethanol, to obtain ligand as white solid, with yield of 4.3 g. 3.56 g Ligand and 1.73 g iridium(III)chloride hydrate were suspended at room temperature under nitrogen in 50 ml 2-ethoxyethanol, obtained yellow suspension was heated, resultant red suspension was filtered, washed with ethanol and hexane, and dried under vacuum, to obtain 4.3 g diiridium complex as bright red powder, with yield of 96%.