Carbon quantum dots (CQDs) are emerging as a promising class of nanomaterials with unique optical, electronic, and chemical properties, making them highly suitable for photocatalytic applications. This mini-review provides a thorough overview of CQD synthesis methods, functionalization techniques, and their photocatalytic uses in environmental remediation and energy conversion. CQDs are particularly effective due to their high surface area, tunable photoluminescence, and efficient charge separation. They show potential in degrading organic pollutants, enhancing hydrogen production via photocatalytic water splitting, and CO₂ reduction. However, challenges such as stability, scalability, and cost-effective synthesis remain. The review discusses these issues and suggests future research directions to optimize CQD performance and scalability, aiming to address global environmental and energy challenges with sustainable solutions.