6-Chloro-5-iodoindole is used in organic synthesis as a building block for more complex molecules, particularly in the development of pharmaceuticals and agrochemicals. Its structure, featuring chlorine at the 6-position and iodine at the 5-position, allows for selective further functionalization, making it valuable in creating compounds with potential biological activity through reactions such as cross-coupling and substitution of the iodine group. It is also employed in research for studying indole derivatives, which are important in medicinal chemistry due to their presence in many natural products and drugs, as well as in materials chemistry for developing fluorescent compounds or highly sensitive sensors.