Reaction of copper(I) chloride with thiophene-2-carbaldehyde thiosemicarbazone (Httsc) in acetonitrile in the presence of Ph 3 P yielded a sulfur-bridged dimer [Cu 2 Cl 2 (μ 2 -S-Httsc) 2 (PPh 3 ) 2 ]·2CH 3 CN (1), while a similar reaction with isatin-3-thiosemicarbazone (H 2 itsc) formed a monomer, [CuCl(H 2 itsc)(Ph 3 P) 2 ]·2CH 3 CN (3). Furan-2-carbaldehyde thiosemicarbazone (Hftsc) also formed a compound of the composition [Cu 2 Cl 2 (Hftsc) 2 (PPh 3 ) 2 ]·2H 2 O (2). Complexes 1–3 have been characterized using elemental analysis, IR, 1 H and 31 P NMR spectroscopy and single crystal X-ray crystallography (1 and 3). Acetonitrile is engaged in hydrogen bonding with the chlorine atom {NCCH 2 –H⋯Cl)}, which is necessary for the stabilization of the bridging sulfur in 1. In compound 3, however, acetonitrile is strongly hydrogen bonded to the NH hydrogen of the isatin ring {CH 3 CN⋯NH(isatin)} and not to the chlorine atom. The Cu⋯Cu contact of 2.7719(5)Å in dimer 1 is close to twice the van der Waals radius of the Cu atom (2.80Å).