Co 2+ and Ni 2+ ions doped β-BaB 2 O 4 nanopowders have been prepared by co-precipitation method and their structural properties are studied by spectroscopic techniques. Powder XRD data reveals that the crystal structure belongs to monoclinic and the average crystallite size is calculated. Optical absorption spectra data reveal octahedral site symmetry for Co 2+ and Ni 2+ ions. Crystal field (Dq) and inter-electron repulsion (B and C) parameters are evaluated for Co 2+ doped β-BaB 2 O 4 nanopowders as Dq=960, B=900 and C=3850cm −1 and for Ni 2+ doped β-BaB 2 O 4 nanopowders, Dq=900, B=850 and C=3500cm −1 . FT-IR spectra showed the characteristic vibrational bands related to BO 3 and BO 4 molecules. Photoluminescence spectra contain the emission bands in ultraviolet and blue regions.