2,3-Naphthalenedicarboxaldehyde (NDA) is primarily used as a fluorescent derivatization reagent for the detection of primary and secondary amines, including amino acids (e.g., proline and hydroxyproline), neurotransmitters, and peptides in analytical chemistry. It reacts readily with amine groups to form highly fluorescent isoindole or related derivatives, enabling sensitive detection via techniques such as high-performance liquid chromatography (HPLC), capillary electrophoresis (CE), and fluorescence spectroscopy. This reagent is particularly valuable for trace-level analysis in biological samples (e.g., plasma, tissue), pharmaceutical quality control, clinical diagnostics, environmental monitoring, and forensic science. Additionally, NDA is employed in sensor development for amine-containing biomolecules and serves as a versatile starting material in organic synthesis for cyclic compounds and specific ligands.