The photo- and electrochemically induced linkage isomerism of six new complexes [Ru(bpy)(2)(L)-(dmso-S)](+), where dmso is dimethylsulfoxide, bpy is 2,2'-bipyridine, and L- is pentachloro-, 2,3,S,6-tetrachloro-, 2,4,5-trichloro-, 2,4-dichloro-, 4-chloro-, and unsubstituted phenylcyanamide anion, were investigated. The quantum yields of linkage isomerism forming the metastable [Ru(bpy)(2)(L)- (dmso-O)](+) complexes are shown to decrease with increasing donor properties of the phenylcyanamide ligand, and it is suggested that the donor properties of the cyanamide ligand stabilize the [Ru(bpy)(2)(L)(dmso-S)](+) complexes in the (MLCT)-M-3 excited state. The cyclic voltammetry of these complexes showed two oxidation processes: a phenylcyanamide L(0/-) couple (an assignment supported by density functional theory (DFT) calculations) and a Ru(III/II) couple at more positive potential. Upon oxidation to Ru(III), the complexes rearranged to form Ru-O linkage isomers, and the scan rate dependent voltammograms permitted estimates of the rates of linkage isomerism.