Nanoclusters (NCs) are meticulously small, kinetically stable, crystalline materials which hold immense potential as multifaceted catalysts for a broad range of biomedical applications. Metal NCs are atomically precise and exist within the range of Fermi wavelength of electrons. They are highly advantageous as functional materials as their physicochemical properties can be customized to meet specific requirements. Copper NCs (CuNCs) are emerging as an efficient substitute to the other existing metal NCs. The synthesis of CuNCs is highly methodical, fast, cost effective and does not involve any complicated manipulation. On the contrary to gold and silver NCs, copper is a vital trace element for humans that can be excreted easily out the body. Further, the relatively inexpensiveness and easy availability of copper aids in potential nanotechnological applications in large quantity. As such, CuNCs have attracted great interest among the research community recently. The modern developments in the strategy, synthesis, surface modifications, and use of CuNCs in diagnosis of disease, imaging and treatment have been discussed in the present review. Approaches to regulate and augment the emission of CuNCs, challenges and drawbacks have also been considered. This review brings to light the multifarious applications of CuNCs and their potential as emerging theranostic agents. It is anticipated that the visions and directions for translating existing developments in CuNCs from the laboratory to the clinic can be further improved and enhanced.