 Carbon dots, CDs, are a type of nanomaterial with unique structural and optical properties. They can be produced using different techniques, but the bottom-up approach remains the most popular due to its cost effectiveness and scalability. This paper provides a detailed review of the synthesis methods for CDs focusing on the bottom-up approach. It then introduces a new classification of CDs called carbonized polymer dots, CPDs. The authors analyze the structure and properties of these materials and discuss how they differ from other types of CDs. Finally, the paper offers insight into the future development of CDs and their potential applications. This article was authored by Chun Lai Xia, Shou Jiu and Zhu, Tang Glufeng, and others.