An ordered head-to-tail (HT) polyurethane was successfully prepared by the polyaddition reaction of p-isocyanatobenzyl isocyanate with ethylene glycol with dibutyltin dilaurate as a catalyst. Furthermore, the HT regularity of polyurethane was improved to 83% with 1,1,3,3-tetraphenyl-1,3-dichlorodistannoxane. The polymerization was conducted in N,N-dimethylformamide at 30 degreesC with both monomers mixed at once. The microstructure of the polymer was investigated by H-1 and C-13 NMR spectroscopy, and the polymer obtained by the polyaddition reaction had the expected HT linkages. The constitutional regularity of the polymers influenced the thermal properties and crystallinity. (C) 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 416-429. 2001.