Copper dioxide (CuO) nanoparticles and Multiwall carbon nanotubes (MWCNTs) filled poly(vinyl alcohol) (PVA) and poly(vinyl pyrrolidone) (PVP) blend matrix (50/50 wt%) based polymer nanocomposites (PNCs) (i.e., PVA/PVP:(15-x)CuO(x)MWCNTs for x=0,1,5,7.5, 10,14, and 15wt%) have been prepared employing the solution-cast method. The morphologies of these PNCs are semicrystalline, according to an X-ray diffraction investigation. The FTIR, SEM, and AFM measurements of PNCs were used to investigate the development of the miscible mix, polymer-polymer and polymer–nanoparticle interactions, and the influence of CuO and MWCNTs nanofillers on the morphology aspects on the main chain of PVA/PVP blend. The nanofiller dispersion signposting for x=14 wt% nanoloading in the PVA–PVP blend matrix significantly enhances the crystalline phase, diminishing the optical energy gap to 2.31eV. The DC conductivity values augment with the upsurge in nanofiller level for maximum x=14wt%. The dielectric and electrical characteristics of these PNCs are investigated for an applied frequency range from 1kHz to 1 MHz. The enhancement in the nanofiller level upto x=14wt% in the PVA/PVP matrix leads to the development of percolating network through the PNCs. These factors boost the dielectric permittivity values substantially, owing to the decrease in the nano-confinement phenomenon. The rise in applied frequency reduces dielectric permittivity and impedance values and enhances ac electrical conductivity. These PNCs having good dielectric and electrical characteristics can be used as frequency tunable nanodielectric material in electronic devices.