Diphenylcarbazone is widely used as an indicator in analytical chemistry, particularly in complexometric titrations for the detection of metal ions. It is highly sensitive to mercury, forming a distinct violet or blue complex, making it valuable in environmental testing to identify mercury contamination in water and soil samples. Additionally, it is employed in the determination of lead, cadmium, and other heavy metals in various industrial and biological samples. Its ability to form colored complexes with specific ions also makes it useful in spectrophotometric analysis for quantitative measurements. In the pharmaceutical industry, diphenylcarbazone is utilized in quality control processes to ensure the purity of products by detecting trace metal impurities.