Dirhodium complexes are effective catalysts in carbene transformations. These reactions involve chemistry between the catalyst and a carbene generated in situ. In order to better understand the rhodium-carbon bond, studies of rhodium acetate, Rh2(OAc)4, and a variety of functionalized benzonitriles were proposed. Diadducts of rhodium acetate with 4-nitrobenzonitrile, 4-aminobenzonitrile, 4-(dimethylamino)benzonitrile, and 3,5-dinitrobenzonitrile were successfully prepared and characterized by X-ray crystallography. IR and NMR spectroscopy were also employed for characterization purposes.