5-Phenoxy-l(3H)-isobenzofuranone, with a phenoxy-substituted benzo five-membered ring lactone structure, is a useful intermediate in preparing the derivatives of isoquinoline. The most common method of preparing 5-Phenoxyisobenzofuran-1(3H)-one was utilized, the copper-catalyzed coupling reaction of 5-bromophthalide and phenol in the presence of a base[1].