End-capped poly(epsilon-caprolactone)s (PCLs) have been prepared elsewhere by various initiators. However, hydroxytelechelic PCLs have been reported less frequently, although there are two hydroxyl end groups ill one polymer chain, which allows diversified functionalization. Two tetrahydrosalen-backboned chlorides containing rare-earth complexes, YbLCl(DME)(2) and ErLCl(DME) {where L is 6,6'-[ethane-1,2-diylbis(methylazanediyl)]bis (methylene)bis(2,4-di-tert-butylphenol) and DME is dimethoxyethane}, were first synthesized ill this study, and they were used as initiator precursors for a ring-opening Polymerization in the presence of NaBH4 to afford hydroxytelechelic PCLs. The polymerization under different condition,, was investigated, and a possible mechanism is proposed. (c) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 557-562, 2009