In this study, polystyrene (PS)/silicon dioxide (SiO₂) nanocomposites were fabricated using an eco-friendly, fluoride-assisted thermochemical synthesis method for nanopar-ticle production. This approach offers a sustainable and scalable route to obtaining high-purity, amorphous SiO₂ nanoparticles, which were subsequently incorporated into a PS matrix to enhance its optical performance. Structural, morphological, and spectroscopic analyses were carried out using SEM, XRD, and Raman spectroscopy. SEM revealed a uniform dispersion of SiO₂ nanoparticles within the PS matrix, while XRD confirmed the amorphous nature of the silica phase. Raman spectroscopy indicated notable changes in the vibrational dynamics of PS upon nanoparticle incorporation, particularly a reduction in phenyl ring bending vibrations, suggesting strong polymer–nanoparticle interactions. The inclusion of SiO₂ not only altered the structural characteristics but also introduced interfacial effects that can modulate the optical behavior of PS. These results demon-strate that incorporating fluoride-synthesized SiO₂ nanoparticles is an effective strategy for engineering PS-based nanocomposites with improved optical properties, making them suitable candidates for applications in optoelectronics and photonic devices.