The present work represents synthesis of a novel Bi3O4Cl/BiOCl heterostructure using precipitation method and detailed characterization of the composite using FT-IR, XRD, FESEM, TEM, BET and EDX techniques. The photocatalytic activity of as-prepared Bi3O4Cl/BiOCl heterostructure was evaluated under visible light and the degradation of levofloxacin drug was studied for a reaction time of 180 min. Under the optimized conditions of catalyst dose 1 g/L, 11 pH, and drug concentration of 10 mg/L, the prepared heterostructure showed high activity i.e. 87% reduction of the drug as compared to bare BiOCl (32%) and BiOBr (57%) catalysts. This enhancement in photocatalytic activity was due to the effective separation of charge carriers at the heterojunction interface. Additionally, the antibacterial activity of the prepared Bi3O4Cl/BiOCl catalyst was evaluated for levofloxacin against Escherichia coli (Gram-negative bacteria) showing zero inhibition. Mineralization studies using TOC analysis was also performed showing 55% Mineralization of the drug under optimized conditions. These finding suggest that Bi3O4Cl/BiOCl composite catalyst was found to be a promising heterogeneous catalyst for drug degradation studies. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.