Ring opening metathesis polymerizations (ROMP) of norbornene (NBE), tetracyclododecene (TCD) in the presence of cis-cyclooctene (COE) using vanadium-alkylidene catalyst, V(CHSiMe3)(N-2,6-Cl2C6H3)(OC6F5)(PMe3)(2) (1), were explored. The polymerizations with TCD afforded high-molecular-weight polymers (M-n=19,500-47,400) with low PDI (M-w/M-n) values (1.18-1.38) which possess microstructure of repeated ringopened TCD and certain methylene units by incorporation of ring-opened COE on the basis of microstructure analysis by NMR spectra and DSC thermograms; hydrogenated copolymer possessed melting temperature at 294 degrees C. (C) 2017 Wiley Periodicals, Inc. J. Polym. Sci.,