This study explores the synthesis and characterization of zinc sulfide (ZnS) nanostructured powder through a chemical methodology. The research systematically evaluates the effects of critical synthesis parameters, such as the mass ratio of the sulfide precursor to the zinc precursor, the pH of the solvent, and the temperature during synthesis. The resulting ZnS samples were extensively characterized utilizing a variety of analytical techniques, including X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), and dynamic light scattering (Zetasizer) analysis. The results of the study revealed that the ZnS powder produced at a pH of 1.2, referred to as ZnS4, exhibited an average particle size of 31 nm, which is considerably smaller than that of other synthesized nano-powders. FTIR spectroscopy analysis confirmed the high purity of ZnS4, indicating a lower absorption edge and diminished levels of impurities in comparison to other synthesized samples. Furthermore, the sintered ZnS4 sample demonstrated an impressive infrared transmittance of approximately 30% within the wavelength range of 8-12 micrometers. This finding underscores the potential of ZnS4 as a viable candidate for applications in infrared optics, including infrared windows and coatings.