Polymerizations of methyl methacrylate with (alpha-diimine)nickel(II)/methylaluminoxane (MAO) and (pyridyl bis(imine))iron(II) and (pyridyl bis(imine))cobalt-(II)/MAO are reported. Effects of structural variation of the ligand on the activities of catalysts and polymer microstructure are described. The catalyst systems gave syndio-rich poly(methyl methacrylate). The alpha-diimine system showed much higher activity than the pyridyl bis(imine) systems under similar polymerization conditions.