trans-Polypentenamers with thermotropic liquid-crystalline side chains cholesteryl and cyanobiphenyl were prepared by ring-opening polymerization of vinylcyclopropane monomers with proper substituents. Molecular weights of the polymers were in the range of 25000 to 80000 and the ratios of weight- to number-average molecular weights (M) over bar(w)/(M) over bar(n) were between 3.3 and 3.8. The glass transition temperature values of the polymers were 35 degrees C (4a) and 39 degrees C (4b). Monomers 3a and 3b present cholesteric and smectic mesomorphism, respectively. On the other hand, polymers 4a and 4b present only a smectic mesophase.