coumarins

https://doi.org/10.1351/goldbook.C01369
2H-Chromen-2-one (older name 1,2-benzopyrone), trivially named coumarin, and its derivatives formed by substitution.
C01369.png
See: isocoumarins
Source:
PAC, 1995, 67, 1307. 'Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)' on page 1328 (https://doi.org/10.1351/pac199567081307)