Novel conjugated stilbenylene polymers are disclosed having non-linear optical properties, and which can be converted to electrically conductive polymers. Such polymers are produced by reacting a novel bis-cycloalkylene sulfonium salt of 2,5-dimethyl stilbene, e.g. 2,5-(4'-methoxy)-stilbene dimethylene bis-(tetramethylene sulfonium bromide), with alkali metal hydroxide to form a cycloalkylene sulfonium salt precursor polymer, and then heating the precursor polymer under conditions to produce the stilbenylene vinylene polymer, e.q. poly(2,5-(4'-methoxy) stilbenylene vinylene).