Layers of ethylene carbonate (EC) modified CuI/PVA polymer composites were prepared by growth of CuI nano-particles in an aqueous solution of PVA followed by casting at room temperature. The structural, thermal, optical, electrical and di-electrical characterization of polymer composites was investigated using different techniques. These investigations confirm the growth of CuI nano-particles and reduction of PVA crystallinity by increasing ethylene carbonate concentration. These results show that energy band gap and bulk conductivity increase while activation energy reduces with the increase of EC concentration in the composite. Moreover, the variation of the dielectric permittivity and dielectric loss with EC content are found to obey Debye dispersion relations.