Arsenazo III is widely used as a metallochromic indicator in analytical chemistry for the detection and quantification of metal ions, particularly rare earth elements, thorium, and uranium. Its ability to form highly colored complexes with these metals makes it valuable in spectrophotometric analysis, where it helps determine metal concentrations in various samples. In environmental monitoring, Arsenazo III is employed to assess the presence of heavy metals in water and soil, aiding in pollution control and remediation efforts. Additionally, it plays a role in biochemical research for studying metal ion interactions with proteins and enzymes, providing insights into cellular processes. Its sensitivity and selectivity make it a crucial tool in both industrial and scientific applications.