The electronic structures and photophysical properties of a series of heteroleptic iridium(III) complexes have been investigated by using the density functional theory. By changing the conjugation length and substituents of the ancillary ligand, one can tune the emission color from blue(lambda(em) = 470 nm) to orange (lambda(em) = 542 nm). -CF3 substituents at different positions at ancillary ligands have an important effect on tuning the emitting color. The larger metal-to-ligand charge transfer character, highest mu(S1) value, and the smallest Delta ES1-T1 value for the complex 6 increase its phosphorescent quantum efficiency than those of other complexes. (C) 2013 Elsevier B. V. All rights reserved.