Several polyurethanes based on bis-@-oxymethylphenyl) terephthalate (BOPT) were synthesized and studied with respect to some of their thermal properties. BOPT exhibits a mesomorphic phase at 252-264ºC. Polymerization was carried out by equimolar reaction with hexamethylene diisocyanate (HDI), 4,4-dicyclohexylmethane diisocyanate (HlzMDI) a,&’-diisocyanate- 1,3-dimethylcyclohexane (H6 XDI), 4,4’-diphenylmethane diisocyanate (MDI), 2,4-tolylene diisocyanate (TDI), and phenylene diisocyanate (PDI). It became clear that polyurethanes obtained from BOPT with HDI, HlzMDI, H6XDI, and TDI have mesomorphic phases at 243-29 1, 2 14-250, 172-229, and 180-234’C, respectively, as determined by DSC and polarized microscopy, and that all polyurethanes are crystalline as evidenced by x-ray diffraction. 1987, Taylor & Francis Group, LLC. All rights reserved.