**5. Conclusions**

Coumarin derivatives are highly valuable lactone-based organic molecules for academics and bio-pharma industries due to the unique nature of chemical properties, and flexible design system to access a broad range of functionalized coumarin scaffolds via simple synthetic chemical transformation as a result, a huge number of coumarin derivatives have been successfully developed and produced in single steps. This review permits many protocols of one-pot construction of coumarins and their derivatives, together with well-studied name reactions and other types of coupling reactions as well using different metal-based catalysis, and visible light-mediated photocatalysis. While these aforementioned traditional name reactions have been employed for several decades, new methods developments have been widely achieved in the last few years such as microwave-, ultrasound-helped, light-induced metal-free radical cyclization, metal-mediated radical cyclization, metal-catalyzed electrophilic cyclization, miscellaneous, homogeneous catalytic reaction and heterogeneous catalytic reaction and solvent-free conditions, This new system were applied in a challenge to maximize the single-pot reaction yield, diminish the reaction time, and reduce the unwanted side reactions and as well as making these reactions more bioactive candidates. This review concluded that this catalysis-based new developments can play an increasing role in the preparation of highly substituted coumarin derivatives by modifying the unpleasant typical reaction conditions associated with the standard synthetic routes.
