Cinchonine sulfate dihydrate is primarily used in the pharmaceutical industry as a precursor in the synthesis of various antimalarial drugs. It plays a crucial role in the production of quinine derivatives, which are effective in treating malaria. Additionally, it is utilized in research laboratories as a chiral resolving agent to separate enantiomers in organic synthesis. Its application extends to biochemistry, where it is employed in studying enzyme inhibition and receptor binding mechanisms. In analytical chemistry, it serves as a standard or reference compound in chromatographic methods for qualitative and quantitative analysis.