PVC/PE polymer nanocomposites were synthesized with 0–3 wt% copper (Cu) nanoparticles via melt extrusion. XRD analysis showed characteristic peaks corresponding to crystalline PVC, PE, and Cu phases. FTIR confirmed the presence of signature vibrational modes of PVC and PE. Optical studies revealed tunable light absorption, refractive index, dielectric response, and bandgap by tailoring copper content. The composites displayed enhanced linear and nonlinear optical susceptibilities, with potential applications in photonics. Optical absorption studies revealed a redshift in bandgap from 3.38 eV to 2.19 eV as Cu concentration increased from 0 to 3%, indicating enhanced visible light absorption. The real dielectric constant rose from 1.3527 to 1.4578 at 190 nm wavelength when Cu content was raised from 0 to 3%. Imaginary dielectric constant exhibited a stepwise enhancement from 2.43 × 10−3 to 3.97 × 10−3 at 190 nm with increasing Cu loading up to 3 %. The nonlinear refractive index varied from 1.2 × 10−8 cm2/W to 2.1 × 10−8 cm2/W across 500–900 nm wavelengths for 0–3% Cu. Meanwhile, the dispersion parameters including, the single oscillator energy (Eo) and the dispersion energy (Ed) were extracted. The relaxation time of the studied samples were extracted, which decreased after the insertion the nanofillers. The outcomes revealed that Cu nanoparticles' doped films favor a high-speed optoelectronic device more than the pristine film. The results demonstrate tunable optical and dielectric characteristics, underscoring the potential of Cu-based PVC/PE nanocomposites.