A series of easily accessible and stable Schiff-base nickel complexes (complex 1-4) in conjunction with methylaluminoxane (MAO) were employed for the synthesis of relatively high molecular weight beta-pinene polymers at high temperature with high productivity. The ligand structure of the complex had a substantial effect on the polymerization in terms of the productivity and the molecular weight. With complex 4 in the presence of MAO, high molecular weight polymers of beta-pinene (M-n similar to 10,900) were obtained at 40 degrees C with an extremely high productivity up to 1.25 X 10(7) g poly beta-pinene/mol of Ni. H-1 NMR analyses showed that the obtained beta-pinene polymer was structurally identical to that formed by conventional cationic Lewis acid initiators. The polymerization was presumably initiated by the nickel cation formed by the reaction of the schiff-base nickel complex and MAO, while the propagation proceeded in a manner typical for a conventional carbocationic polymerization process. Direct evidence for the carbocationic polymerization was offered by the fact that quenching of the polymerization with methanol at a low monomer conversion resulted in incorporation of a methoxyl end group into the polymer chain. (C) 2007 Wiley Periodicals, Inc.