Anionic polymerizations of 2-[2-(4-ethenylphenyl)ethenyl]-4,4-dimethyl-2-oxazoline (1), 2-[2-(4-isopropenylphenyl)ethenyl]-4,4-dimethyl-2-oxazoline (2), and 2-[1-methyl-2-(4-ethenylphenyl)ethenyl]-4,4-dimethyl-2-oxazoline (3) were carried out in tetrahydrofuran at -78 degrees C with (1,1,4,4-tetraphenylbutanediyl)dipotassium. Poly(1) was quantitatively obtained after 24 h but the molecular weight distribution (MWD) of the polymer was relatively broad (M-W/M-n = 1.3-1.4). The H-1 NMR analysis of the polymer suggested that side reactions toward the conjugated C=C-oxazoline linkage occurred during the polymerization. No apparent polymerization of 2 was observed under similar condition. On the other hand, the polymerization of 3 proceeded rather rapidly within 1 h and quantitatively gave poly(3) having a narrow MWD (M-W/M-n < 1.1) and the predicted molecular weight based on the molar ratio of monomer to initiator. The living character of the propagating carbanion of poly(3) was confirmed by the quantitative initiation efficiency in the postpolymerization. Novel tailored block copolymers, poly(3-b-isoprene-b-3), poly(3-b-styrene-b-3), and poly(tert-butyl methacrylate-b-3-b-tert-butyl methacrylate), were synthesized by sequential block copolymerizations of 3 and corresponding comonomers. It was elucidated from the results of block copolymerization that anionic polymerizability of 3 was higher than that of styrene and could be estimated to be the same level of 2-vinylpyridine. The oxazoline protecting moiety of poly(3) was completely hydrolyzed by treating with 3 N HCl in THF and subsequently with 15% NaOH (aq) in MeOH to give a well-defined poly(4-vinyl-alpha-methylcinnamic acid). The resulting poly(8-vinyl-alpha-methylcinnamic acid) could be quantitatively converted into its methyl ester by the reaction with diazomethane. The UV irradiation of poly(3) and poly(methyl 4-vinyl-alpha-methylcinnamate) at room temperature gave insoluble materials in moderate yields, indicating the photo-cross-linkable potential of these polymers.