Anionic polymerizations of seven styrenes para-substituted with N-arylimino groups were carried out in THF at -78 degrees C with oligo(alpha-methylstyryl)dipotassium and -dilithium as the initiators. The N-aryl functionalities contained phenyl (1), 2-(tert-butyl)phenyl (2), 2,6-dimethylphenyl (3), 2,6-diethylphenyl (4), 2,6-diisopropylphenyl (5), 4-cyanophenyl(6), and 2,3,4,5,6-pentafluorophenyl (7) groups. The monomers 3-5 underwent anionic polymerization quantitatively to produce the polymers having predicted molecular weights based on molar ratios of monomers to initiators and narrow molecular weight distributions, the M-w/A(n) values being around 1.1. On the other hand, no polymeric products were obtained from the polymerization mixture of 1, 2, 6, and 7 under identical conditions. The bulkiness of the two ortho alkyl substituents on the N-aryl moiety was necessary to achieve the anionic living polymerization of styrenes bearing N-arylimino groups. Well-defined new block copolymers having poly(5) segments were synthesized by the sequential addition of 5 and styrene or tert-butyl methacrylate. The resulting poly(3-5) could be quantitatively transformed into the poly(4-formylstyrene) having tailored chain structures by the acid hydrolysis of N-arylimino moieties.