Cadmium sulphide thin films were successfully synthesized by the flash evaporation method under vacuum, then annealed at various temperatures. X-Ray Diffraction patterns showed the formation of the hexagonal wurtzite phase. Structural properties of this most stable phase remain approximately the same at all investigated temperatures. Scanning Electronic Microscopy showed the formation of granular films. The Energy Dispersive X-ray spectra revealed the possible formation of stoichiometric compounds. The obtained UV-Vis spectra revealed that the prepared films exhibit a moderate direct band gap with high transmittance in the visible range. Detailed interpretation of the structural, optical, and optoelectronic findings revealed that annealed CdS thin films hold promising potential for the fabrication of the next generation of the modern optoelectronic devices. Cadmium sulphide thin films were successfully synthesized by the flash evaporation method under vacuum, then annealed at various temperatures. X-Ray Diffraction patterns showed the formation of the hexagonal wurtzite phase for all temperatures with almost the same structural properties. UV-vis spectra revealed that the prepared films exhibit a moderate direct band gap with high transmittance in the visible range, which reinforces the usefulness of these films for photovoltaic and photocatalytique applications. Scanning Electronic Microscopy shows the formation of granular films, while the Energy Dispersive X-ray spectra revealed the possible formation of stoichiometric compounds.