2H-Furo(2,3-h)-1-benzopyran-2-one, known as angelicin, is a naturally occurring angular furocoumarin. It is primarily utilized in photochemotherapy for treating skin disorders like psoriasis and vitiligo, where it intercalates with DNA and forms photoadducts upon UVA exposure to inhibit excessive cell proliferation, with lower mutagenicity than linear psoralens. It functions as a fluorescent probe in biological imaging due to strong UV emission and favorable cell membrane permeability for intracellular tracking. In photodynamic therapy, it serves as a photosensitizer producing reactive oxygen species under light. As a building block, it aids synthesis of advanced coumarin derivatives with pharmaceutical promise. Research highlights its anti-inflammatory and antioxidant effects, including inhibition of enzymes in chronic inflammation pathways, potential for treating arthritis or neurodegenerative diseases, and anticancer activity against sensitive cell lines. It also features in sensors for metal ion detection, such as aluminum and zinc, in environmental monitoring.