2-Carboxybenzaldehyde is a metabolite of the biodegradation of luoranthene from two bacterial strains, Pasteurella sp. IFA (B-2) and Mycobacterium sp. PYR-1 (AM). 2-Carboxybenzaldehyde is a carboxylated derivative of benzaldehyde which is readily converted to 2-hydroxymethyl benzoic acid by CBA dehydrogenase. 2-Carboxybenzaldehyde has been used to synthesize a series of N-substituted isoindolinones by reductive C-N coupling and intramolecular amidation with amines.