A senior undergraduate project in inorganic chemistry is described, involving the reaction of copper(II) bromide and the potential bidentate sulfur ligand bis(N,N-dimethylthiocarbamoyl) sulfide (N,N,N',N'-tetramethylthiuram monosulfide). The students are required to interpret the unusual pattern of reactivity observed, and to characterize the products generated, bromo-bis(N,N-dimethylthiocarbamoyl)sulfidocopper(I) and 2,5-bis(N,N-dimethyliminium)-1,3,4-trithiolane tribromocuprate(I), by means of elementary analyses, infrared spectroscopy, and magnetic susceptibility measurements. Additional topics for discussion are suggested. The behavior of the reactants in this system would not normally be evident to students at an undergraduate level, but would be accessible after rigorous interpretation of the experimental evidence.