Bathophenanthrolinedisulfonic acid disodium salt trihydrate is widely used as a chelating agent in analytical chemistry, particularly for the detection and quantification of iron ions. Its high affinity for iron makes it a valuable reagent in colorimetric assays, where it forms a distinct red-colored complex with ferrous iron (Fe²⁺), enabling precise measurement of iron concentrations in various samples, including water, biological fluids, and industrial solutions.

In environmental science, it is employed to monitor iron levels in natural water bodies, helping to assess water quality and detect contamination. In biochemical research, it is utilized to study iron metabolism and its role in cellular processes, providing insights into diseases related to iron imbalance, such as anemia or hemochromatosis. Additionally, it serves as a stabilizer in certain industrial applications, preventing unwanted iron-catalyzed reactions. Its water solubility and stability make it a practical choice for these diverse applications.