The radical reaction between hexaphenylcyclohexaarsine (1) and acetylenic compounds with various substituents (2a-d) using a catalytic amount of AIBN provided the corresponding alternating copolymer, poly(vinylene-arsine). The copolymers obtained were soluble in common organic solvents such as THF, chloroform, benzene, and toluene. From gel permeation chromatographic analysis (chloroform, Pst standards), the number-average molecular weights of the copolymers were found to be several thousands. Structural characterization of the copolymers was provided by H-1 and C-13 NMR spectroscopies. The measurement of the conversion rate of 2a-d during the copolymerization by using gas chromatography gave an evidence to support the assumption that the formation of vinyl radicals by addition of arsenic radicals to acetylenic compounds was the rate-determining step in this copolymerization system. The copolymer obtained showed fluorescence properties which were influenced by the substituents of the acetylenic compounds.