Used primarily as an intermediate in organic synthesis, especially in the pharmaceutical and agrochemical industries. It reacts readily with amines to form indole-based amides, which are key structural motifs in bioactive molecules. Commonly employed in the development of serotonin receptor ligands and other neuroactive compounds due to the indole core’s prevalence in neurotransmitters. Also utilized in the preparation of fluorescent probes and dyes, where the indole scaffold contributes to light absorption and emission properties. Its reactivity allows for efficient derivatization in combinatorial chemistry and drug discovery pipelines.