Mono- and dinuclear salphen-type complexes were developed and investigated in CO2/epoxide copolymerization reactions. Kinetic investigations indicate that the reaction occurs predominately in a bimetallic fashion in the absence of cocatalysts for both mono- and dinuclear complexes. The dinuclear system, therefore, maintains its activity even under highly diluted conditions of [PO]/[M] = 20000 at which the mononuclear system loses its efficiency. The effect of the nature and amount of added cocatalyst on catalytic performance was investigated as well, indicating a binary propagation mechanism both in mononuclear and dinuclear systems in the presence of cocatalysts.