4-Hydroxycoumarin, a coumarin derivative, is one of the most versatile heterocyclic scaffolds and is frequently applied in the synthesis of various organic compounds. 4-Hydroxycoumarin possesses both electrophilic and nucleophilic properties. 4-Hydroxycoumarin derivatives are employed as the anticoagulant, antibacterial, antifungal, antiviral, antitumor, antiprotozoal, insecticidal, antimycobacterial, antimutagenic, antioxidant, anti-inflammatory agents, HIV protease inhibitors and tyrosine kinase inhibitors.