Ca2+ substituted barium niobate i.e. CaxBa1-xNb2O6 (x=0.3) compound in nanoparticles form was synthesized by a simple co-precipitation method for the first time and its structural characterization has been done by using powder X-ray diffraction data. Other characterizations were done by using transmission electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy. It was found that the CaxBa1-xNb2O6 (x=0.3) compound stabilizes in the orthorhombic phase (Pbcn space group) with the lattice parameters a = 14.984 angstrom, b = 5.761 angstrom and c = 5.216 angstrom. A representative TEM image shows the irregular sphere like morphology of the synthesized particles with the size ranging from 70 to 120 nm. The optical band gap energy was found to be 3.74 eV. It was observed that the synthesized nanoparticles exhibit excellent H-2 evolution tendency and self-activated photoluminescence under the excitation of UV light. These activities were assigned to the nanocrystalline nature of the synthesized material. (C) 2016 Elsevier Ltd. All rights reserved.