This study synthesized a series of titanium iminophenoxide complexes and investigated their suitability as catalysts for the ring-opening polymerization of L-lactide (L-LA) and e-caprolactone (CL). Complexes with bidentate ligands demonstrate higher catalytic activity than their tridentate counterparts since the third coordination atom needs to contend with L-LA and CL. Differences in the geometric framework of bidentate ligands also influence the catalytic activity. Type II ligands (N, N-trans form of Ti complex) prevent the coordination of monomers to Ti thereby decreasing the initiation rate. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013