Flexible dielectric polymer nanocomposites (NCs) with high dielectric permittivity and low loss factor have numerous applications in light emitting and storage devices. In this research work, polymer based NCs in the form of flexible sheets containing 5% ZnO and 15, 20% SiO₂ nano-fillers, are synthesized by using co-precipitation method. X-ray diffraction analysis reveals the development of various diffraction planes related to ZnO and SiO₂ phases confirms the synthesis of polycrystalline PB–ZnO–SiO₂ NCs flexible sheets corresponding to various compositions. Morphology and compositional analysis show the uniform distribution of nanoparticles in polymer matrix with estimated elemental contents in each composition. Dielectric measurements demonstrate a sharp increase in dielectric permittivity with relatively low dissipation factor in synthesized compositions having ZnO and SiO₂ nano-fillers. The static value of dielectric constant at 100 Hz is found to be 10.79 for sample having 20% SiO₂ nano-fillers that is 3.4 times greater than pure PVA and it shows relatively low value of dissipation factor. The observed AC conductivity of synthesized NCs flexible sheets having 5% ZnO, 20% SiO₂ nano-fillers is 2.15 × 10^–5 S/m that is 3.3 times greater than pure PVA at 1 × 10⁶ Hz. Complex impedance spectroscopy further confirms, these materials as promising candidates for better capacitive performance.