<p>This work proposes a novel multi-factorial theoretical model for calculating the relative permittivity and refractive index of nanosolids. The model incorporates the influence of several key factors, including particle size, shape, dangling bond, and packing factor on the relative permittivity and refractive index. The computation of the relative permittivity and the refractive index through the model, for Si, CdSe, CdS, CdTe, ZnSe, ZnS and ZnTe semiconducting nanomaterials in various shapes demonstrates that the dielectric constant and the refractive index lower down as the particle shrinks in size and the particle undergoes a morphological transformation from a perfect sphere to a regular tetrahedron. Our computed findings when compared with the available experimental data closely match the observations from the experiment, thus authenticating the present wide-ranging picture. This study proposes that the current model for predicting the dielectric constant and refractive index of nanomaterials. The model’s applicability extends to materials lacking prior experimental study within the nanoscale regime.</p>