Used as a derivatizing agent in analytical chemistry, particularly for the detection and quantification of alcohols and phenols in high-performance liquid chromatography (HPLC). It reacts with hydroxyl-containing compounds to form colored or fluorescent derivatives, enhancing their detectability. Also employed in the synthesis of dyes and sulfonamide intermediates. Its strong electron-withdrawing nitro group facilitates nucleophilic substitution reactions, making it useful in organic synthesis for introducing sulfonic acid functionality into aromatic systems.