<p>Copper sulphide (CuS) nanomaterials have emerged as multifunctional materials owing to their unique electronic structure, tuneable optical properties, and excellent physicochemical stability. In particular, nanoscale CuS exhibits localized surface plasmon resonance (LSPR) in the near-infrared (NIR) region, high electrical conductivity, and strong catalytic activity, making it highly suitable for a wide range of engineering applications. This paper presents a comprehensive discussion on the structural, optical, and electrochemical properties of CuS nanomaterials, followed by their synthesis strategies and performance in energy storage, environmental remediation, sensing, and photothermal engineering applications. The role of morphology control and composite engineering in enhancing functional performance is also emphasized. The findings suggest that CuS nanomaterials are promising candidates for next-generation multifunctional engineering devices.</p>