Wiktionary
isoindole
n. (context organic compound English) A bicyclic heterocycle that is an isomer of indole
Wikipedia
Isoindole
Isoindole in heterocyclic chemistry is a benzo-fused pyrrole. The compound is an isomer of indole. Its reduced form is isoindoline. The parent isoindole is a rarely encountered in the technical literature, but substituted derivatives are useful commercially and occur naturally. Isoindoles units occur in phthalocyanines, an important family of dyes. Some alkaloids containing isoindole have been isolated and characterized.