Polyvinyl chloride (PVC) was used as a host matrix for different CdSSe nanoparticles (NPs) concentrations. PVC-CdSSe films were prepared by the solution-cast method, and CdSSe NPs were prepared by the hot-injection method. A scanning electron microscope attached to an EDX unit was used to identify CdSSe elements. The reinforcement of CdSSe NPs in the PVC matrix exhibits growth in CdSSe particle size due to agglomerations. PVC-CdSSe films were examined via XRD, FT-IR, and a polarized optical microscope. The roughness tester was used to measure the surface roughness parameters of the PVC-CdSSe films, which revealed the growth in film roughness with increasing the CdSSe concentration. The UV-visible spectrophotometer was used to analyze the PVC-CdSSe film's transmission and absorption. Tauc's model was used to evaluate the optical bandgap (E-g). The E-g was lessened from 5.45 eV for pure PVC to 4.78 eV for PVC-3wt%CdSSe film, while the Urbach energy was increased upon CdSSe NPs additive to the PVC matrix testifying to the formation of the localized states with high-density. Furthermore, an improvement in nonlinear optical parameters (estimated via the Wemple-DiDomenico model) was observed. The third-order nonlinear optical susceptibility ( chi((3))) enhanced from 4.08 x 10(-15) for pure PVC to 1.91 x 10(-13) for PVC-3wt%CdSSe, due to the surface plasmon oscillation of CdSSe NPs in the PVC matrix. In view of the improved optical parameters, the as-prepared PVC-CdSSe films make them a possible nominee for nonlinear optical devices.