4-Iodoquinoline is primarily used as an intermediate in the synthesis of pharmaceuticals and biologically active compounds. Its structure serves as a building block in the development of antimalarial and anticancer agents, where the iodine atom allows for further functionalization through cross-coupling reactions such as Suzuki or Heck reactions. It is also employed in the preparation of fluorescent probes and sensors due to the quinoline core’s inherent photophysical properties. In medicinal chemistry, derivatives of 4-iodoquinoline have shown potential in targeting DNA and inhibiting specific enzymes involved in disease pathways. Additionally, it finds use in research settings for labeling and radioimaging applications when tagged with radioactive iodine isotopes.