Carbon dots (CDs) as an emerging carbon nanomaterial have attracted considerable attention and have been widely used in numerous fields. When compared with semiconductor quantum dots and organic dyes, CDs have a low toxicity, good biocompatibility and good anti-photobleaching. These qualities give them the potential to be a greener optical probe than other types of quantum dots and organic dyes. Covering several common synthesis strategies, including biomass synthesis, large-scale synthesis and sustainable synthesis technology, this book focuses on the green synthesis of CDs and their applications in the fields of bioanalytical, catalytic, biomedical, and environmental sciences. It is a useful reference for anyone working in green chemistry, analytical chemistry, biomedical or environmental science.