<p>This work focuses on examining how the nanomaterials influence the structural and optical properties of the prepared nanocomposites (NCs). So for this purpose, magnesium oxide (MgO) and silicon dioxide (SiO₂) nanoparticles (NPs) were incorporated into a Polyvinyl pyrrolidone—Polyethylene glycol (PVP–PEG) matrix using the casting process to create new NCs suitable for optoelectronic applications. Field-emission scanning electron microscopy (FESEM) and Fourier transform infrared (FTIR) tests confirmed the uniform distribution of nanofillers and interaction with the polymer blend in real ways. The transmittance and indirect optical energy gap were reduced with the addition of Mg⁺² and Si⁺² ions. The improvement in refractive index values was 24.10% in the Vis (500nm, rises from 1.358 for polymer blend to 1.789 for 6wt% SiO₂) and 26.4% in NIR (1100nm, rises from 1.247 to 1.696 for 6wt% SiO₂). Other findings regarding the optical properties indicated that the extinction coefficient k, real and imaginary dielectric constants, and optical conductivity of PVP–PEG increased with the increasing content of nanofillers. The refractive index was further analyzed using the Wemple–Di Domenico to extract dispersion parameters: These parameters showed a significant improvement in optical characterizations, going from the single-oscillator energy E_o (6.69 to 6.18) eV, dispersion energy E_d (2.68 to 12.71) eV, and static refractive index n_s (1.25 to 1.7). Moreover, the moments of optical spectrum M_₋₁ and M_₋₃&#xa0;increased from (0.57 to 1.87), and (0.026 to 0.041), while the oscillator strength f_o (12.5692 to 55.6698). The atomic diffusion into interstitial regions within the polymer blend matrix is responsible for this enhancement. Ultimately, the PVP-PEG/MgO-SiO₂ NCs are a viable choice for optoelectronic devices, as indicated by the obtained results.</p>