The radiopacifying organobismuth monomer p-styryldi(p-tolyl)bismuth was synthesized in 40% yield by means of a three-step process using 4-bromotoluene, 4-bromostyrene and bismuth trichloride as starting compounds. The product is a crystalline solid of at least 95% purity, unlike the earlier reported styryldiphenylbismuth which could only be obtained in a very impure form. Radical or anionic polymerization yields a soluble homopolymer, and copolymers were made with styrene and methyl methacrylate. The products were characterized by standard techniques. Data are reported on their solubility, blending and radiopacity. The latter property, expressed in mm of aluminium per mm resin, is a linear function of the molar bismuth concentration in the polymer specimens.