Osmium metal complexes are of interest as they exhibit visible luminescence upon excitation with visible or ultraviolet light and as such are possible models of photosynthetic reaction center, possible energy and electron transfer agents, and possible photochemical or electrochemical reaction catalysts. Recently we have synthesized a series of bis-(diimine)carbonylalkylosmium(II) complexes using 2,2-bipyridine and 1,10-phenanthroline and alkyl ligands such as methyl, ethyl, butyl and isopropyl. We will discuss the synthesis of these complexes which yield both cis- and trans- isomers that are isolated and have their own individual electrochemical and photochemical properties. The characterization of the electronic states of these compounds by UV-visible absorbance and ¹H NMR spectroscopies will also be discussed. We will discuss our conclusions about the effect of these ligand variations on the electronic properties of these compounds.