Used as a key intermediate in the synthesis of pharmaceuticals, particularly in the development of kinase inhibitors and antimicrobial agents. The chloride group at position 6 and carboxylic acid at position 3 enable selective modification, making it valuable in medicinal chemistry for designing compounds with enhanced biological activity. It is also employed in research settings to develop new isoquinoline-based drugs targeting inflammatory diseases, certain cancers, and central nervous system disorders. Additionally, it serves as a building block in agrochemicals for creating novel pesticides with improved efficacy.