A kinetic study of a syndiospecific polymerization was performed with two kinds of catalysts: Cp*Ti(O(C6H4)CMe2(C6H4)O)TiCp* [bimetallic system] and Cp*Ti(OMe)(3) [monometallic system]. The purpose of this study was to determine the reasons behind the high activity of a bimetallic catalyst system. The active site structures of the two kinds of catalysts appears to be similar to the cationic Ti[III] species having eta(5)-pentamethylcyclopentadienyl ligand, while the rate of the activation process of the bimetallic catalyst was found to be higher than that of the monometallic catalyst. (c) 2007 Wiley Periodicals, Inc.