Indoline is an aromatic heterocyclic organic compound with the chemical formulation C<sub>8</sub>H<sub>9</sub>N. It has a bicyclic structure, consisting of a six-membered benzene ring fused to a five-membered nitrogen-containing ring. The compound is based on the indole structure, but the 2-3 bond is saturated. By oxidation/dehydrogenation it can be converted to indole.
Indoline can be produced from the reaction of indole, zinc and 85% phosphoric acid. It was used to make Indocaine.