In recent times, metal oxide-organic nanocomposites have received great attention because of their feasibility to wide range applications such as super capacitors, antibacterial activity, biomedical sensors, battery applications and microfluidic devices. In this work, zinc oxide-chitosan (ZnO-CS) and their novel tin zinc oxide-chitosan (SnZnO-CS) hybrid nanocomposites successfully synthesized by a simple one-pot sol-gel reaction. The equal metal oxide ratio such as 0.5, 1.0, 1.5 and 2.0% (W/V) for zinc and tin sources with constant weight of chitosan were used to prepare the SnZnO-CS nanocomposites. Fourier transform infrared spectroscopy results proved the formation of SnZnO-CS nanocomposites. X-ray diffraction patterns discovered the mixed phase polycrystalline nature of SnZnO-CS nanocomposites. Optical and luminescence properties were extensively studied for nanocomposites by UV-Vis and photoluminescence spectroscopy, respectively. The surface modification elaborately discussed with scanning electron microscope images due to incorporation of SnO with ZnO-CS matrix. The antibacterial properties of SnZnO-CS were tested against Escherichia coli, Salmonella Typhi and Klebseilla Pneumoniae bacterial species.