The synthesis of ring-opening metathesis polymerization (ROMP) chain transfer agents (CTA)s bearing methacrylate or epoxide end functionality was accomplished. In the presence of these CTAs, the ROMP of cyclooctadiene (COD) initiated with (PCy3)(2)Cl2Ru=CHPh afforded the respective telechelic poly(butenylene)s with either methacrylate or epoxide end groups. Control over the polymer molecular weight was demonstrated by varying the COD/CTA ratio; Successful cross-linking by thermal or photochemical initiation of the bis(methacrylate)-functionalized telechelic poly(butenylene)s or through acid catalysis of the bis(epoxide)-functionalized telechelic poly(butenylene)s was accomplished. While crosslinking was found to reduce solubility of the polymers, it greatly enhanced their thermal stability.