Composite samples of polyvinyl chloride/polystyrene (PVC/PS) blend filled with copper chloride (CuCl2) were synthesized by the solution casting technique. The XRD and SEM analyses implied the presence of CuCl2 crystallites in PVC/PS polymeric blend. The FTIR spectra depicted the compatibility of the blend components and the formation of interactions between the functional groups of PVC/PS matrix and the Cu2+ ions. In the UV region, the UV/Vis. spectrum of PVC/PS showed the CUT-OFF range that was largely increased after the filler addition. Further, the optical parameters were determined. The dielectric and alternating current electrical conductivity spectra of polymer composites had been investigated at room temperature in the frequency range from 100 Hz to 1 MHz. The effect of prepared composite samples on the antifungal properties of Aspergillus avenaceus and Aspergillus terreus is scrutinized and has been tested by the agar disk diffusion technique. Further, the fungal biomass, catalase activity, and protein content were investigated. Moreover, SEM revealed that blend surfaces with 8% CuCl2 displayed a noticeable diminishing in fungal hyphal net framework, reduced density and inhibition on hyphal growth. The results indicated that composite samples with the highest CuCl2 concentration are more toxic to both fungal species. The multifunctional properties of these prepared samples depict their suitability as a base matrix for composite solid polymer electrolytes, dielectric substrate for the optoelectronic/ microelectronic devices. Also, it can be utilized as a promising material for excellent UV/Vis. optical limiting and UV-protector and a novel antifungal agent to control the pathogenic fungi.