In this work, a novel polyimide (PI) was prepared using bis(4-aminophenoxy)dimethylsilane and napthyldianhydride and the resulting PI was further reinforced with varying weight percentages (1%, 3%, 5%, and 10 wt%) of amine-functionalized bio-silicon (FSi) derived from rice husk to obtain hybrid nanocomposites. The dielectric, thermal, surface, and ultraviolet (UV) shielding properties of both PI and hybrid PI nanocomposites were thoroughly investigated. It was observed that the reinforced FSi acts as a mini capacitor embedded in the PI packing and contributes to high dielectric constant (5.8) as well as low dielectric loss. Moreover, the distribution of FSi throughout the PI matrix also offers superior hydrophobicity (95.1° in water) and enhanced thermal stability (36% char yield) to those of neat PI. Furthermore, the hybrid nanocomposites possess higher UV shielding behavior in both UV-A (97.2%) and UV-B (95.8%) region than those of neat PI. Based on the experimental findings, it is concluded that the bio-mass-based FSi-reinforced PI nanocomposites can be utilized as printed circuit board material or antistatic coating material with improved performance and enhanced longevity under different environments.