TBD catalyzed continuous flow ring-opening polymerizations of epsilon-caprolactone and delta-valerolactone were exemplified as the model investigation system of organocatalytic synthesis of polyesters in the simple PTFE tubular microreactor (MR). In contrast to the batch reactor (BR), significant benefits of utilizing continuous flow strategy were achieved including higher level control of molecular weights and molecular weight distributions as well as faster polymerizations (k(app)(CL) = 0.00602 (MR) vs 0.00286 min(-1) (BR); k(app)(VL) = 0.159 (MR) vs 0.079 min(-1) (BR)). Furthermore, more easily and efficiently block co-polymerizations were conducted in the integrated-microreactor by sequential introduction of monomers to well-defined poly(delta-valerolactone)-block-poly(epsilon-caprolactone) and poly(e-caprolactone)-block-poly(delta-valerolactone). (C) 2016 Elsevier Ltd. All rights reserved.