Dithiodiolate ligands were synthesized by reacting 1,2-ethanedithiol or 1,2-benzenedithiol with 2,2-bis(trifluoromethyl)oxirane, led selectively to mononuclear octahedral group 4 complexes of the type [{OSSO}M(OR)(2)], which features C-2 symmetry and fluxional behavior, and were highly active in the ring-opening polymerization of rac- and L-lactide.