AbstractHigh molecular weight, 1:1 alternating copolymers of 1‐bicyclobutanecarbonitrile with styrene were prepared in tetramethylenesulfone solution by complexing the electron‐poor bicyclobutane monomer with zinc chloride. Methyl 1‐bicyclobutanecarboxylate under these conditions gave copolymers containing a slight excess of styrene units (ratio 1:1.3 to 1:1.8). High molecular weight homopolymers of 1‐bicyclobutanecarbonitrile and of methyl 1‐bicyclobutanecarboxylate were prepared similarly. The tendency of the bicyclobutane nitrile to form 1:1 alternating copolymers is as great as that of its vinyl analog, acrylonitrile, and the synthesis of other alternating copolymers from this monomer should be