Isopotential points are described in multicycle voltammograms of N,N’-bis(salicylidene)ethylenediaminato-cobalt(III)perchlorate in mixtures of dimethyl formamide and pyridine. The potentials where these points occur vary with the solvent composition. The results are discussed in terms of the three-rung ladder scheme describing the electrode reaction with electron exchanges (Co(II) half arrow right over half arrow left Co(III)) at the electrode surface and the successive exchange of two solvent molecules per complex.