In order to tune the emission to be pure red and increase the efficiency, new iridium complex, Ir(PF-piq)(2)(acac), is designed and studied, where piq, PF-piq and acac represent phenylisoquinoline, 4-(perfluorophenyl)-1-phenylisoquinoline and acetylacetonate, respectively. The Hartree-Fock (HF) method with the 3-21G(d) basis set and density functional theory (DFT) utilizing the B3LYP functional with the 6-31G(d) basis set were used for the geometry optimization and the energy level calculation of the ground state of this complex, respectively. The excited triplet and singlet states are examined using the time-dependent density functional theory (TD-DFT). As a result, it is confirmed theoretically that the wavelength of new iridium complex were shifted toward the red region when introducing a pentafluorophenyl group. The efficiency and brightness of the complex are predicted to increase in comparison with those of Ir(piq)(2)acac.