The Polyvinyl alcohol (PVA)-Ag/Coumarin nanocomposite films with various Coumarin concentrations have been prepared and analyzed. The optical properties and dispersion parameters have been determined. The PVA semicrystalline nature has been ensured by using X-ray Diffraction (XRD). The crystallinity degree decreases with the rise in Coumarin concentration. Scanning electron microscope (SEM) images show that the Ag nanoparticles are distributed all over the surface. Increasing the concentration of Coumarin in PVA-Ag nanocomposites leads to an increase in refractive index, absorption coefficient, and Urbach energy. It also results in a significant decrease in both the energy band gap and the relaxation time. The optical conductivity and dielectric constant were enhanced as well, with the concentration of Coumarin rising. Wemple–Di Domenico single oscillator model has been utilized to calculate the nonlinear optical properties. It was evident that with the rise in Coumarin concentration, the values of nonlinear optical properties n_2, x^((1)) , and x^((3)) have increased. As a result, the PVA-Ag/30wt coumarin's good optical characteristics make it ideal for optical applications.