Two anthracene-based complexes [Ir(pbt)(2)(aip)]Cl (1) and [Ir(pbt)(2)(aip)]Cl (2) have been synthesized based on the ligands aip = 2-(9-anthryl)-1H-imidazo[4,5-f][1,10]phenanthroline, aipm = 2-(9-anthryl)-1-methyl-imidazo[4,5-f][1,10]phenanthroline, and pbtH = 2-phenylbenzothiazole in order to explore both the influence of the substituent group R-1 (R-1 = H in 1 and CH3 in 2) on photo-oxidation activity and photo-oxidation-induced luminescence. Both H-1 NMR spectra and ES mass spectra indicate that the anthracene moiety in complex 1 can be oxidized at room temperature upon irradiation with 365 nm light. Thus, this complex shows photo- oxidation-induced turn-on yellow luminescence. Compared to 1, complex 2 incorporates an R-1 = CH3 group, resulting in very weak photo-oxidation activity. On the basis of experimental results and quantum chemical calculation, we report the differences between 1 and 2 in both photo-oxidation behavior and the related luminescence modulation and discuss the relationship between photo-oxidation activity and substituent group R-1 in these complexes.