The reduction at the mercury electrode of a series of copper(11) dithiocarbamates [CU(S2CNR2)2] in propylene carbonate has been investigated by a variety of electrochemical techniques. Thecomplexes undergo reduction in two successive one-electron diffusion-controlled steps, with associated adsorption of the complexes and the reduction products. Exhaustive reduction at a mercury-pool electrode shows the completely reduced species [CU(S2CNR2)2]2- to undergo slowdissociation. The alkyl substituent influences the strength of adsorption of the reduction products, the reduction potentials of the complexes and the reversibility of the first reduction step, thesecond step being quasi-reversible in all cases. The electroactive centre appears to be the metal.