High-molecular-weight para-type homopolyurethanes prepared by polyaddition of 2,5-tolylene diisocyanate with 4,4＇-bis(omega-hydroxyalkoxy)biphenyls showed monotropic liquid crystallinity, when measurements were performed under shearing. For example, a polyurethane PU6T having [eta] 0.82 which was obtained from 4,4＇-bis(6-hydroxyhexyloxy)biphenyl showed TI-LC of 201 degrees C and TLC-K of 181 degrees C. In addition, thermotropic liquid-crystalline para-type copolyurethanes PUmnT (m and n denoting carbon number in alkylene moiety : 2, 6, 8, and 11) were synthesized by polyaddition of the diisocyanate with two 4,4＇-bis(omega-hydroxyalkoxy)biphenyls having different alkylene lengths. For example, PU68T(75/25) had TI-LC of 188 degrees C and TLC-K of 173 degrees C. Blends of two para-type homopolyurethanes also exhibited monotropic liquid crystallinity. The liquid crystallinity was examined by differential scanning calorimetry measurement, polarized optical microscope observation, and X-ray diffractometry.