Well-defined poly(caprolactone) PCL samples of narrow molecular weight distribution, tagged with a triazole junction in predetermined position of the chain, were synthesized by an alkyne-azide click reaction. The crystallization kinetics of these original PCL's, having a triazole "defect" in central position or at the chain end, were investigated by WAXD and by differential scanning calorimetry (DSC) under nonisothermal and isothermal conditions. Major kinetic differences could be observed between the triazole end-capped PCL and the one having a triazole "defect" in central position of the chain. The crystallization rate is highest for the triazole end-capped PCL, whereas a PCL with a triazole junction in more central position forms irregular shaped spherulites and is characterized by a longer induction period, a lower crystallization rate and a reduced maximum melt temperature. Its thermostability as demonstrated by thermogravimetry analysis TGA, is however increased with respect to the corresponding triazole end-capped sample. (C) 2011 Elsevier Ltd. All rights reserved.