A new series of cationic heteroleptic iridium(III) complexes with phenanthroline based-ancillary ligands, namely, [Ir(ppy)(2)(dmphen)]PF6, [Ir(ppy)(2)(dbphen)]PF6 and [Ir(ppy)(2)(dpphen)]PF6 (ppy is 2-phenylpyridine, dmphen is 2,9-dimethyl-1,10-phenanthroline, dbphen is 2,9-dibutyl-1,10-phenanthroline, dpphen is 2,9-diphenyl-1,10-phenanthroline and PF6 is hexafluorophosphate) have been synthesized and characterized by various spectroscopic methods. These synthesized complexes were used for the fabrication of single component light-emitting electrochemical cells (LECs). The electroluminescent devices were evaluated on the basis of electroluminescence properties and the effect of substituents on the phenanthroline ligands tune the emission color of the complexes.