Pseudo-successive ionic layer adsorption and reaction (p-SILAR) process was opted for deposition of PbS/CdS and CdS/PbS quantum-dots (QDs) on TiO2 to combine light absorbing tendency of PbS and CdS QDs which evolved significant photocatalytic behavior in TiO2 under visible light irradiation. It was shown that the resultant TiO2/PbS/CdS hierarchical nanocomposite exhibited better photo-electrochemical behavior than TiO2/CdS/PbS, ensuing similar to 42% higher degradation of acid orange-56 than the latter and similar to 65% higher than pristine TiO2. In addition, both nanocomposites resulted promising antibacterial activity against Escherichia coli (E. coli). Particularly TiO2/PbS/CdS showed much greater inhibition zone (similar to 14 mm) than TiO2 (similar to 8 mm).