Sodium 2,3-dihydroxynaphthalene-6-sulfonate is widely used as a reagent in analytical chemistry, particularly for the detection and determination of metal ions. It forms colored complexes with various metals, making it useful in spectrophotometric analysis. For example, it is employed in the quantification of iron, aluminum, and other transition metals in environmental and industrial samples. Additionally, it serves as an intermediate in the synthesis of dyes and pigments, contributing to the production of vibrant and stable colors for textiles, inks, and coatings. Its water-soluble nature and ability to chelate metals also make it valuable in water treatment processes, where it helps in the removal of heavy metals from wastewater.