•Ca2YTaO6 an intrinsic broad band blue emission originated from the TaO6 group.•The crystal structure, and the electronic characteristics were detailed investigated.•The blue emission was efficiently tuned to cyan, red and white.•Efficient energy transfer observed intrinsic blue emission to Bi3+ and Eu3+ ions. Display omitted Novel tunable-color emitting phosphors with double perovskite structure un-doped, single and co-doped with Bi3+/Eu3+ ions were successfully synthesized by the high-temperature solid state reaction method. The crystal structure, band-gap, and electronic structure were investigated by using computational methods. The morphology and phase composition were obtained with scanning electron microscopy and powder x-ray diffraction. The un-doped Ca2YTaO6 phosphors shows an intensive intrinsic emission centered at 424 nm under 315 nm UV light excitation. The obtained intense blue emission (424 nm) was efficiently tuned to cyan, red and white light with doping of Bi3+ and Eu3+ as a result of energy transfer.