High Quality Content by WIKIPEDIA articles! Isoindoline is an aromatic heterocyclic organic compound with the molecular formula C8H9N. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered nitrogen-containing ring. The compound`s structure is similar to indoline except that the nitrogen atom is in the 2 position instead of the 1 position of the five-membered ring.