Electrochemical behaviour and interconversion of mononuclear [Mn-II(bpea)(2)](2+) (3), binuclear [Mn-2(III,III)(mu-O) (mu-OAc)(2)(bpea)(2)](2+) (2) and [Mn-2(IV,IV)(mu-O)(2)(mu-OAc)(bpea)(2)](3+) (1) (bpea = N,N-bis(2-pyridylmethyl)ethylamine) complexes have been investigated in acetonitrile solution. Controlled potential oxidations at 0.5 and 1.0 V in the presence of added acetate anions allow the selective and nearly quantitative formation of (2) and (1), respectively, from (3). Similar transformations have been obtained if (3) is formed in situ by direct mixing of Mn2+ cations and bpea ligand with a 1:2 stoichiometry, Associated electrochemical back transformations have also been investigated in detail.