1,10-Phenanthroline monohydrate is widely used as a chelating agent in analytical chemistry, particularly for the determination of metal ions such as iron. It forms stable, colored complexes with iron(II), making it a key reagent in spectrophotometric methods for measuring iron concentrations in various samples, including water, biological fluids, and industrial materials.

In biochemistry, it serves as a ligand in studies of metalloenzymes and metal-protein interactions, helping researchers understand the role of metal ions in biological systems. It is also employed in the synthesis of coordination compounds and catalysts used in organic reactions, owing to its ability to stabilize metal centers.

Additionally, 1,10-Phenanthroline monohydrate finds application in corrosion inhibition, where it acts as a protective agent for metals by forming a barrier against corrosive substances. Its versatility in forming complexes with transition metals makes it valuable in both research and industrial settings.