Synthesis of selenium-containing syndiotactic polystyrene through coordination polymerization is difficult to achieve since selenium atoms usually poison the applied catalysts. Herein, we report the coordination polymerization of para-methylselenostyrene (pMSS) and its copolymerization with styrene (St) using pyridyl- methylene-fluorenyl-supported complexes [(Py-CH2-Flu)Ln(CH2SiMe3)(2)(THF)(n) (Ln = Y (1), n = 1; Ln = Sc (2), n = 0)]. Complex 1 was completely inert, while complex 2 was highly active and exhibited >99% syndioselectivity to yield poly(pMSS) as the rare crystalline polymer-containing selenium atoms in side chains. In addition, the copolymerization of polar pMSS with nonpolar St under various pMSS-to-St ratios proceeded smoothly. The excellent syndiotacticity was maintained in the copolymerization, and the obtained copolymers have random sequence distributions confirmed by C-13 NMR spectrum analysis and kinetics study. The optical performances of the copolymers with different incorporations of selenium were studied.