The anionic polymerization behaviors of ethynylstyrene derivatives containing isomeric pyridine moieties, 2-(2-(4-vinylphenyl)ethynyl)pyridine (A), 3-(2-(4-vinylphenyl) ethynyl) pyridine (B), and 4-(2-(4-vinylphenyl) ethynyl) pyridine (C), were investigated in the identical conditions. The anionic polymerization of A-C was performed with (diphenylmethyl) potassium (Ph(2)CHK) in tetrahydrofuran (THF) at -78 degrees C. The polymerization of A proceeded quantitatively at -78 degrees C for 4 h, and the resulting poly(A) possessed predictable molecular weights (M(n) = 3300-68,500) and narrow molecular weight distributions (MWDs) (M(w)/M(n) = 1.04-1.11). In contrast, the anionic polymerization of B was not performed at -78 degrees C for 4 h due to the occurrence of side reactions. The monomer B was quantitatively recovered after the reaction. In the polymerization of C performed at -78 degrees C for 6 h, observed Mn values of the resulting poly(C) were in good agreement with calculated molecular weights based on monomer to initiator ratios, but the MWDs were somewhat broad (M(w)/M(n) = 1.23-1.31). To estimate the reactivity of A and to characterize its living nature, the block copolymerization of A with 2-vinylpyridine (2VP) and methyl methacrylate (MMA) was performed. The well-defined block copolymers, poly(2VP)-b-poly(A) and poly(A)-b-poly(MMA), were successfully synthesized without any additives. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 5199-5209, 2011