In this article, a new type of strongly dimerizing 2-ureido-4-[1H]-pyrimidinone (UPy) with amine group is synthesized and then used as end-group to prepare a novel series of supramolecular polyurethanes (PUs). The effects of strong and well-defined hydrogen bonding on material properties of PUs are studied. In these PUs, the UPy groups consequently serve as thermoreversible associations or the "hard blocks'' and the bi-functional PU chains act as the "monomers.'' This theoretical hypothesis is proved by the results of dynamic mechanical thermal analy-sis (DMTA) and rheological test. Thermal analysis shows that the strong hydrogen bonds from end groups restrict the formation of their microcrystalline domains. The supramolecular PUs exhibit good mechanical performance and their self-assemble mechanism is discussed. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123: 1755-1763, 2012