The electronic structures, photophysical properties, and potential organic light-emitting diodes (OLEDs) applications of a series of Ir(III) complexes 1-6 have been theoretically investigated by using the density functional theory (OFT) method. The photophysical properties of these complexes are greatly affected by the different substituents on the cyclometalated ligands. The phosphorescence wavelength, quantum yields, and luminescent efficiency of these complexes also are closely related to the pi-conjugation length, substitution positions, and substituents inductive effect for the cyclometalated ligands. The designed complex 5 could be a potential candidate as a blue-emitting material with a high quantum efficiency. (C) 2014 Elsevier B.V. All rights reserved.