Abstract The absorption spectrum of Mn2+ ions doped in diglycine barium chloride monohydrate (DGBC) has been studied at liquid nitrogen temperature (77 K) in the region λ 6000 A to 3000 A. Three of the observed bands showed well resolved fine structure. The splitting of 4Eg (G) band is explained as due to exciton-magnon interaction. Weak bands on either side of 4A1g (G) band are assigned to phonon progressions withν = 200 cm The fine structure of the 4T2g (D) band is analysed in terms of spin-orbit splitting associated with the vibrational frequency of the hydrogen bond (185 cm−1). The observed band positions are fitted with four parameters B,C, Dq and α, and the best fit is obtained with B = 810 cm−1, C = 2980 cm−1, Dq = 760 cm−1 and α = 76 cm−1. justify our assumption of octahedral site symmetry for the metal ion in the crystal. From the observed absorption spectrum it is possible to determine the crystal phonons in Mn2+ doped DGBC and it is found to be about 200 cm−1.