<p>This study presents a comprehensive analysis of the structural, electronic, mechanical, and thermal properties of wurtzite-phase cadmium sulfide (CdS) colloidal nanocrystals (NCs), combining experimental data with theoretical modeling. X-ray diffraction confirmed the wurtzite crystal structure, while UV–Vis absorption and Tauc plot analysis determined the optical bandgap. First-principles density functional theory (DFT) calculations were employed to investigate the electronic and mechanical properties, revealing a direct bandgap of 1.59&#xa0;eV and lattice parameters that closely match experimental measurements. The calculated elastic constants (<i>C</i>₁₁, <i>C</i>₁₂, and<i> C</i>₄₄) confirmed the mechanical stability of CdS NCs, while thermodynamic analysis provided crucial insights into their thermal behavior. These findings demonstrate strong agreement with experimental data and offer a deeper understanding of CdS NCs’ stability and performance. This work bridges gaps in the mechanical property analysis of CdS NCs and contributes to optimizing CdS-based optoelectronic devices. </p>