Used primarily as a developer in photographic processes, particularly in black-and-white photography, to produce high-quality images. It acts as a reducing agent, converting exposed silver halide crystals into metallic silver, which forms the image. Additionally, it finds application in dye synthesis, particularly in the production of azo dyes, which are widely used in textiles and printing industries. Its role in analytical chemistry includes use as a reagent for detecting and quantifying certain chemical compounds.