Prevention of future threat of antibiotic-resistant bacteria and genes by elimination of discharged antibiotics from environment pleas for growth of cutting edge technologies with high efficiency. Herein, CdS QDs modified BiOI-Bi doped Bi₂MoO₆ nanocomposite (BOI-CBBMO) was synthesized by in-situ precipitation deposition method. The unique composite with 3% CdS QDs i.e. BOI-CBBMO-3 exhibits best degradation performance of four ubiquitous antibiotics i.e. 87%, 87% 75% and 93% for tetracycline, oxy-tetracycline, ciprofloxacin, norfloxacin in 60 min of sunlight irradiation and ^•OH is mainly responsible for degradation process. Real environmental factors like pH, inorganic salts are also considered for degradation. The chemical interaction exists between catalyst and antibiotics are ascertained by zeta potential and contact angle experiment. This evidenced hydrophobic-hydrophilic interaction rather electrostatic interaction. Intermediate products are detected Liquid Chromatography-Mass Spectrometry analysis reveals presence of no anti-bacterially active products.