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Five cyclometalated iridium(III) complexes containing phenyl-azole ancillary ligands were synthesized and characterized by X-ray crystallography, and their photophysical properties were studied. [Display omitted] In this study, five cyclometalated iridium complexes containing phenyl-azole ancillary ligands were synthesized and characterized by X-ray crystallography, and their photophysical properties were studied. The reaction of [Ir(ppy) 2 (μ -Cl)] 2 (ppy: 2-phenylpyridine) with pim (4-phenylimidazole), ptr4h (4-phenyl-4 H -1,2,4-triazole), and ptr1h (1-phenyl-1 H -1,2,4-triazole) ligands furnished mononuclear [Ir(ppy) 2 Cl L ] complexes (1 – 3 ; L = pim, ptr4h, ptr1h) featuring monodentate neutral N → Ir coordination. In contrast, the corresponding reaction with ptz (5-phenyl-1 H -tetrazole) ligand yielded a hetero-bridged dimeric iridium complex, [Ir(ppy) 2 (μ -Cl)(μ -ptz)Ir(ppy) 2 ] (4). Notably, adding dimethylsulfoxide (DMSO) solvent to complex 4 resulted in its division to [Ir(ppy) 2 (ptz)(DMSO)] (5) and [Ir(ppy) 2 Cl(DMSO)]. Complexes 1 – 4 exhibited blue-green phosphorescence in solution with marginal shifts in the emission wavelengths. Complex 1, having a pim ligand, exhibited a significantly higher phosphorescence quantum efficiency (Φ PL = 31%) than those of complexes 2 – 4 (Φ PL = 4–9%), which was attributed to the relatively small non-radiative decay rate constant in 1. Density functional theory calculations confirmed that the phosphorescence has originated from both the metal–ligand charge transfer (3ML ppy CT) and the ligand-centered (3LC ppy) states. An increased LC character was observed in the phosphorescence of the dinuclear complex 4. [ABSTRACT FROM AUTHOR]