<p>In this work, we report the preparation and performance of Graphene-ZnS/PEDOT:PSS-based hybrid nanocomposites for the fabrication of photodetectors. The XRD study reveals an ordered crystalline nature of ZnS NPs, which is significantly influenced by the interaction between graphene (GR) and the ZnS lattice. SEM images show that the ZnS NPs are uniformly distributed on the surface of the graphene NPs, indicating better material uniformity. The PL spectra of the nanocomposite display green light emission across a wide spectral range, signifying the presence of structural defects. These materials substantially improve the photodetector’s performance, as shown by I-V measurements (photoconductance), due to superior charge transport that results in a fast response time. Graphene NPs enhance electrical conductivity and inhibit recombination, while PEDOT:PSS facilitates charge accommodation and reduces internal resistance. Notably, the photoconductive UV light detection behavior of the Graphene:ZnS/PEDOT:PSS nanocomposite also exhibits outstanding performance, with a maximum quantum efficiency of 0.6 × 10³ and a high responsivity of 25.14 × 10⁻⁷ A/W under 320 nm illuminations. These findings demonstrate that the Graphene:ZnS/PEDOT:PSS nanohybrid is a promising candidate for high-performance, high-speed photodetectors.</p>