3-Aminophthalic acid serves primarily as a key intermediate in the organic synthesis of chemiluminescent compounds, notably luminol (3-aminophthalhydrazide). It is obtained by reduction of 3-nitrophthalic acid and subsequently reacted with hydrazine to form luminol. This derivative is crucial in forensic applications for the presumptive detection of blood traces at crime scenes, where luminol reacts with the iron in hemoglobin to produce a characteristic blue chemiluminescent glow in the presence of an oxidant like hydrogen peroxide. Furthermore, luminol and related compounds derived from 3-aminophthalic acid are utilized in biochemical and immunological assays for sensitive detection of biomolecules through light emission upon oxidation. In research, it contributes to the development of fluorescent probes, sensors, and other light-emitting materials for analytical and diagnostic purposes.