New heteroleptic tris-cyclometalated iridium complex having two different (C boolean AND N) ligands, [Ir(dpq)(2)(dpq- 3F)] (dpq = 2,4-diphenylquinoline, dpq-3F = 2-(3'-fluorophenyl)4-phenylquinoline), have been synthesized and characterized for an efficient red organic light-emitting diodes (OLEDs). The iridium phosphors emit bright red light with its maximum at 608 nm. The heteroleptic tris-cyclometalated iridium complex [Ir(dpq) 2(dpq- 3F)] is shown to be a more efficient electrophosphor than the homoleptic tris-cyclometalated iridium complex [Ir(dpq- 3F)3] to avoid the T-T annihilation by decreasing the number of the luminescent ligand. A maximum luminous efficiency was 10.9 cd/A at a current density of J = 0.6mA/cm(2). At a higher current density of J = 100mA/cm 2, the luminous efficiency maintained 54% of its maximum value as 5.9 cd/A.