Syndiotactic copolymers with p-methylstyrene, p-tert-butylstyrene and a-methylstyrene were obtained using fluorinated half-sandwich catalyst systems. In the presence of p-alkylstyrenes the activities were high. The incorporation fo p-alkylstyrenes is nearly as good as it is for sytrene. Molar masses increase using p-alkylstyrene comonomers. The steric hindrance of the a-methyl group in a-methylstyrene results in low activities and poor incorporation rates. Since the melting points of the copolymers are lower than the melting point of the sytrene homopolymer the products are easier to process. Crystalline p-tert-butylstyrene-rich copolymers were obtained if appropriate crystallization procedures were carried out.