The photocatalytic activity of ZnO:Mo/GCN (ZnO:Molybdenum/g-C3N4) thin films deposited using a simple cost-effective jet nebulizer spray pyrolysis technique with different Mo doping concentrations (1,2 and 3 at.%) was studied. The photocatalytic degradation test was carried out against Methylene blue (MB) and Rhodamine B (RhB) dyes under visible light. It is found that thin film of ZnO:Mo/GCN with 1 at.% of Mo exhibits superior photocatalytic efficiency compared with the other samples. The degradation rate constant of this sample is 0.0727 and 0.0268 min(-1) for the tested MB and RhB dyes, respectively which are nearly two times and four times greater than the respective rate constant values of pristine ZnO. The mechanism involved in the enhanced photocatalytic activity is addressed with the help of obtained results. The properties of the deposited samples are correlated appropriately with the photocatalytic efficiency of the samples. The photostability of the prepared catalysts is tested experimentally.