Neocuproine hydrate is widely used in analytical chemistry as a selective chelating agent, particularly for the determination of copper ions. It forms a stable complex with Cu(I), which is useful in spectrophotometric assays to measure copper concentrations in various samples, including environmental and biological materials. Additionally, it serves as a reagent in biochemical research to study copper-dependent enzymes and processes. Its application extends to organic synthesis, where it acts as a catalyst or ligand in specific reactions, enhancing efficiency and selectivity.