Hydrogenase enzymes have attracted much attention over the last decade due to their ability to convert protons to molecular hydrogen, which can then be converted into energy. Much of the work done to understand the mechanism of these enzymes has been toward the goal of an efficient, cost effective, and clean production of hydrogen for use in fuel cells. The work presented here involves computational and photoelectron spectroscopic studies on a series of potential catalyst systems. These systems contain the Fe2S2(CO)6 group as the catalytic center, and substituents have been added to this “backbone” via the sulfur atoms to form terminal or bridging thiolate ligands; substituents studied include alkyls, aryls, hydroquinones, and stannylated groups. Of primary interest is how these varying groups influence both the electronic and geometric structures of these systems. Comparisons to theoretical calculations have been performed to assess their validity with respect to experimental data. By gaining an understanding of the basic trends ligands may have on these systems, predictions for future, more efficient catalysts can be formulated.