Newly prepared and well-characterized nanocomposite thin films of polyvinylpyrrolidone (PVP), containing GdCl3 with percentages of 2, 5, 10, 15 and 20% by weight, are studied to investigate the effect of dopant concentration on the thermal properties, stability and degradation up to higher temperatures (500 oC) utilizing differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). A thermal transition of decomposition nature has been recorded for all samples in the range from room temperature to 150 oC. The heat consumed during this transition has showed a monotonic decrease with increasing dopant concentrations. Thermogravimetry has showed two degradation phases; at lower and higher temperature. Increasing the dopant concentration remarkably minimized the rates of degradation for the higher temperature phase. The effect of dopant concentration on the opto-dielectric properties was also investigated and the optical parameters, such as refractive index, extinction coefficient, real and imaginary parts of the dielectric constant and optical conductivity, were studied on the basis of optical data.