Isoquinoline-3-carboxylic acid monohydrate is primarily utilized in the field of medicinal chemistry as a key intermediate in the synthesis of various biologically active compounds. It serves as a building block for the development of pharmaceuticals, particularly in the creation of alkaloid derivatives that exhibit therapeutic properties. Its structural framework is valuable in designing molecules with potential anti-inflammatory, antimicrobial, and anticancer activities. Additionally, it is employed in research settings to study enzyme inhibition and receptor interactions, aiding in the discovery of new drug candidates. In organic synthesis, it is used to construct complex heterocyclic compounds, contributing to advancements in chemical and pharmaceutical industries.