We offer a synthesis of novel nanocrystalline ZnBiVO4 using hydrothermal method. The same novel catalyst was synthesized using solid-state route for the first time. We have exemplified the hydrothermal synthesis of this new compound using zinc nitrate, bismuth nitrate and ammonium metavanadate. The ZnBiVO4 was synthesized using zinc oxide, bismuth oxide and vanadium oxide by solid-state route. X-ray difractometry for its structural study and Scanning Electron Microscopy for the particle morphology characterized the resultant product. The prima facie observations revealed the formation of tetragonal crystallites of hydrothermal ZnBiVO4 ranging from 40-50nm. The BET surface area of hydrothermal ZnBiVO4 was increased 9 times as compared to solid state ZnBiVO4. The steepness of the UV-visible DRS Diffuse Reflectance Spectra) absorption edge, suggests the good crystalline nature of the material. From the photodecomposition of H2S, it is noteworthy that the hydrogen evolution was enhanced by 70% in hydrothermal ZnBiVO4.