We report the synthesis and characterization of copper-indium binuclear I-III complexes composing the series (Ph3P)(2)Culn-(SEI)(x)Cl4-x (1-5, 0 <= x <= 4) Members of the series, which are prepared by vanations in the stoichiometry, are compared in terms of their solid-state structures, spectroscopic features, and suitability as precursors for CuInS2 materials The regiochemistry of thiolate substitution, the preference for monomeric versus dimeric (eight-membered ring) structures, and new synthetic strategies informed by this senes are all discussed.