Quorum sensing-IN-7 (compound HSL 4) is a potent quorum sensing (QS) inhibitor. Quorum sensing-IN-7 interacts with Leu 72 and Gln 95 in the CviR binding pocket. Quorum sensing-IN-7, an antibacterial agent, is highly effective at inhibiting the production of homoserine lactones (HSLs) and biofilm in C. violaceum at 0.25-1 mg/mL.