Meso-Lactide was polymerized in bulk at 60, 80, and 100 °C by means of three different types of catalysts: dibutyltin sulfides (2,2-dibutyl-2-stanna-1,3-dithiolane and 2,2â²-dibutyl-2-stanna-1,3-dithiane), dibutyltin derivatives of substituted catechols (BuCa, CyCa, and BzCa), and dibutyltin derivatives of 2,2â²dihydroxybiphenyl (SnBi) and 2,2â²-dihydroxy-1,1â²-binaphthyl (SnNa). Only the latter two catalysts were active at 60 °C. The architecture of the resulting polylactides depends very much on the structure of the catalyst and on the temperature. At the lowest temperature (60 °C), SnBi and SnNa mainly yielded even-numbered linear chains, but SnNa also yielded even-numbered cycles at 100 °C and short reaction times. In contrast, BuCa, CyCa, and BzCa mainly yielded odd-numbered cycles, although the same catalysts yielded even-numbered linear chains when benzylalcohol was added. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 749â759. © 2018 Wiley Periodicals, Inc.