A cyclobutene monomer, methyl cyclobutene-1-carboxylate (MHCB), has been polymerized by anionic addition polymerization. Although MHCB may be regarded as a member of alpha, beta-disubstituted acrylate derivatives which are reluctant to undergo anionic addition polymenzation. anionic polymerization of MHCB with tert-butyllithium (t-BuLi) in combination with bis(2,6-di-tert-butylphenoxy)ethyl-aluminum [EtA](ODBP)(2)] in toluene at -78degreesC gives a polymer consisting of 1,2-linked cyclobutane ring in the main chain with narrow molecular weight distribution. Copolymerization of MHCB and methyl methacrylate with t-BuLi[EtAl(ODBP)(2) proceeds in a monomerselective and living manner to form a block-like copolymer. Poly(MHCB) undergoes unique thermal reaction through ring opening of the cyclobutane units to form C = C bonds between successive monomer units. (C) 2004 Elsevier Ltd. All rights reserved.