Osmium metal complexes exhibit visible luminescence upon excitation with visible or ultraviolet light. These compounds are of interest as possible models of the photosynthetic reaction center, as energy and electron transfer agents, and as photochemical or electrochemical reaction catalysts. As part of an ongoing study to explore the versatility of the cis-bis-(diimine)carbonyltriflatoosmium(II) precursor, we have synthesized a series of luminescent cis-bis-(diimine)carbonyltriphenylphosphineosmium(II) complexes. We have explored the effects of substituents on both the diimine and the triphenylphosphine ligand. We will discuss the results of the synthesis and purity of these complexes by proton, carbon and phosphorus NMR as well as infrared spectroscopy.