Radiation-induced polymerization of acrylonitrile in frozen agueous ZnCl$_2$ solution was conducted at low temperature. the marked enhancement of both the rate and degree of polymerization was observed in the presence of ZnCl$_2$ which implied the formation of ZnCl$_2$-acrylontrile complex in the system. The rate of polymerization, R was found to be presented as R∽〔M-ZnCl2〕2${ imes}$I where, I is the dose rate and 〔M-ZnCl2〕is the concentration of the M-ZnCl2 -acrylonitrile complex which indicated the dual role of the complex in the polymerization, i.e., in the production of radical species responsible for initiation and enhanced effect on the propagation.