**1. Introduction**

Coumarin heterocycle is an award gifted from nature, coumarins get the name from "Coumarou" which is the vulgarity term of the plant that belongs to the Fabaceae family named tonka bean. The natural product of coumarin and its scaffolds were isolated and purified by Vogel in 1820 [1], and it was prepared by Perkin in 1868 [2]. The lactones-based ubiquitous heterocyclic coumarins have been known as fragrance products in perfumes, because of their nature of sweet smell. Naturally appearing coumarins and their analogs are known in about 700 chemical

structures in more than 100 plant families [3] and remarkably, the number of core structures of coumarin derivatives still increases. Coumarins (2*H*-1-benzopyran-2 one) are one the most important heterocyclic compounds and their scaffolds are an essential class of lactone family with a fused α-pyrone ring attached to a benzene moiety. The centre core of coumarins has shown great interest over the years because of their significant biological importance and applications [4–14]. This type of fused oxygen heterocycles is associated with a wide range of biological properties like antitubercular, anti-inflammatory, anticancer, anticonvulsant, and neuroprotective, such as antiviral, antifungal, antibacterial, antihyperglycemic, anticoagulant, antihypertensive, antiadipogenic, anti-HIV, antibacterial, antimicrobial and antioxidant, etc. effects.

Moreover, coumarins analogs are attracting the vital attention of chemists due to their broad range of materials applications like photosensitizers, fluorescent, optical brighteners [15, 16], and laser dyes [17, 18], and additives [19] in food, cosmetics, and pharmaceuticals, etc.

In this particular lactone based coumarin family of drug molecules such as warfarin [20], acenocoumarol [21], and phenprocoumon [22] are the most prominent ones, which are currently used in a many different nations (**Figure 1**). Due to their unique nature and greater half-life, notably, warfarin is used more often compare to acenocoumarol. These results highlight a significant new development in the biological evaluation of coumarins and their derivatives, as well as medicinal chemistry [23–30]. As a current result, the

**Figure 1.** *Representative examples of lactone-based bioactive coumarin-based derivatives.*
