Indole-6-carboxaldehyde is a chemical reagent used in the synthesis of antitumor agents and botulinum neurotoxin serotype a protease inhibiting analogs.

Indole-6-carboxylic acid methyl ester is a reagent used in the preparation of pharmaceuticals. It has been used to synthesize inhibitors blocking NS5B polymerase and histamine H1 blockers, along with cGMP-PDE inhibitors. It has also been used in the synthesis of antibacterial agents.

Through inhibition of superoxide dismutase, IPA has shown to protect against oxidative damage in primary neurons and neuroblastoma cells. IPA has also shown to protect against death caused by exposure to amyloid β-protein in primary neurons and neuroblastoma cells.

Chromogenic substrate for beta-D-galactosidase, yielding a green precipitate upon cleavage