A general method for the preparation of polyarylether alternating copolymers containing pendent cyano groups has been developed. We found that the activated aryl fluorides in 2-chloro-6-fluorobenzonitrile are selectively displaced by phenoxides to yield 3-chloro-2-cyanophenyl ethers as the exclusive products. Utilizing this selectivity, several new, high molecular-weight, soluble polyarylether alternating copolymers containing pendent cyano groups were prepared by sequential reaction of 2-chloro-6-fluorobenzonitrile with the potassium salts of two different diphenols. Reaction of two moles of 2-chloro-6-fluorobenzonitrile with one mole of a diphenoxide yields a bis(3-chloro-2-cyanophenyl)ether (bis-CCPE) as the only product. Subsequent reaction of a second bisphenoxide with the bis-CCPEs causes displacement of the activated chloro groups and formation of alternating copolymers. The copolymers were processable from solution to yield transparent, flexible films. At elevated temperatures the cyano groups undergo crosslinking reactions yielding films with high solvent resistance. The glass transition temperatures of the resulting crosslinked films ranged from 156 to 254 degrees C depending on polymer structure and cure conditions.