Eriochrome Cyanine R is widely used as a metallochromic indicator in analytical chemistry, particularly for complexometric titrations. It is effective in determining metal ions like aluminum, iron, and zirconium by forming colored complexes, which helps in identifying the endpoint of titrations. In environmental testing, it is utilized to measure water hardness by detecting calcium and magnesium ions. Additionally, it serves as a dye in histology for staining tissues, aiding in microscopic analysis. Its ability to bind selectively with specific metals makes it valuable in both laboratory research and industrial quality control processes.