Copper oxide (Cu₂O) is a potential material as a catalyst for CO₂ reduction. Cu₂O nanostructures have many advantages, including interfacial charge separation and transportation, enhanced surface area, quantum efficiency, and feasibility of modification via composite development or integration of the favorable surface functional groups. We cover the current advancements in the synthesis of Cu₂O nanomaterials in various morphological dimensions and their photochemical and electrochemical applications, which complies with the physical enrichment of their enhanced activity in every application they are employed in. The scope of fresh designs, namely composites or the hierarchy of copper oxide nanostructures, and various ways to improve CO₂ reduction performance are also discussed in this review. Photochemical and electrochemical CO₂ transformations have received tremendous attention in the last few years, thanks to the growing interest in renewable sources of energy and green facile chemistry. The current review provides an idea of current photochemical and electrochemical carbon dioxide fixing techniques by using Cu₂O-based materials. Carboxylation and carboxylative cyclization, yield valuable chemicals such as carboxylic acids and heterocyclic compounds. Radical ions, which are induced by photo- and electrochemical reactions, as well as other high-energy organic molecules, are regarded as essential mid-products in photochemical and electrochemical reactions with CO₂. It has also been claimed that CO₂ can be activated to form radical anions.