The synthesis and photophysical study of efficient phosphorescent iridium(III) complex having two different (C boolean AND N) ligands are reported. In order to improve the luminescence efficiency by avoiding triplet-triplet (T-T) annihilation and study luminescent mechanism of the heteroleptic iridium complex, Ir(piq-3F)(2) (dpq-4F) is designed and prepared where piq-3F and dpq-4F represent 1-(4'-fluorophenyl)isoquinoline and 2-(3'-fluorophenyl)-4-phenylquinoline, respectively. We thought that both piq-3F and dpq-4F ligands can act as a source of energy supply because of the relative HOMO energy level and the luminescence lifetime of homoleptic Ir complexes Ir(piq-3F)(3) Ir(dpq-4F)(3). However the UV-vis absorption spectra and the PL spectra of Ir(piq-3F)(2) (dpq-4F) is more similar to that of Ir(piq-3F)(3). In spite of lower triplet energy level of dpq-4F, the excitation energy is not intramolecular transferred from two piq-3F ligands to one dpq-4F ligand. The luminescence occurs mainly at piq-3F ligand. It is due to the strong MLCT characteristic of piq-3F ligand. To analyze luminescent mechanism, we calculated these complexes theoretically by using computational method.