Nomenclature of acid anhydride
It looks like a isochroman-1,3-dione to me.

For the reference there is a similar compound (published in French): Kakou-Yao, R.; Saba, A.; Ebby, N.; Pierrot, M.; Aycard, J. P. Tautomérie de la 4-(hydroxyphénylméthylène) isochroman-1,3 dione à l'état solide, Acta Cryst C 1999, 55 (9), 1591–1593. DOI: 10.1107/S0108270199006782