© 2021 Bentham Science Publishers.Background: Indole-based heterocyclic compounds play important roles in pharmaceutical chemistry due to their unexpected biological and pharmacological properties. Objective: Herein, we describe novel biological properties (antioxidant, antimicrobial and anti-cancer) of 3-bromo-1-ethyl-1H-indole (BEI) structure. Method: BEI was synthesized from 1-Methyl-2-phenylindole and N-bromosuccinimide and was characterized by using 1H and 13C NMR. Cytotoxicity was determined by MTT assay. Apoptosis analysis of BEI was determined by Arthur™ image-based Cytometer. Different methods were applied to assess the antioxidant activity of BEI. Molecular docking studies were conducted to determine the interactions of bonding between GST isozymes and BEI. Results: According to the antioxidant and antimicrobial activity assays, BEI compound showed reduced total antioxidant activity compared to the Trolox standard, whereas it showed moderate antimicrobial activity against Aspergillus niger and Phytophora eryhtrospora. Notably, the BEI compound demonstrated substantial selective cytotoxicity for the first time towards cancer cell lines, and there existed a significant decrease in the percentage of live cells treated with BEI, in comparison to the control ones. Interestingly, BEI exhibited a promising glutathione S-transferase isozymes inhibition. Conclusion: The results of this study suggest that BEI seems to be a promising molecule to be used in the design of new anti-cancer agents that provide superiority to present commercial anti-cancer drugs.