Photo-sensitive probes based on coumarin deserve extensive attention because of their high biocompatibility, quantum yield, and stability. The synthesis of coumarin and its derivatives is mainly based on four classical methods: Perkin synthesis, Knoevenagel synthesis, Wittig synthesis, and Pechmann synthesis. As everyone knows, fluorescent probes consist of a recognition group, a bridging group, and a luminescent group. Mechanism of fluorescent probes can be roughly summarized into four models: Chelation-induced enhanced fluorescence (CHEF), intramolecular charge transfer (ICT), photoinduced electron transfer (PET), and aggregation-induced luminescence (AIE), which can instruct the design of coumarin-based photo-sensitive probes. Since the fluorescence-based probe was first reported, probes based on coumarin have found widespread application in analytical chemistry, proving to be a selective, efficient, and convenient tool in ion monitoring, molecular monitoring, cell imaging, drug delivery, and many other fields. In this critical review, the synthetic routes of these compounds and the design for fluorescent probes were reported. Furthermore, the recent researches on the employment of coumarin in analytical chemistry were also introduced. Finally, the future research trends and application foreground of coumarin derivatives were forecasted herein.