Emerald coloured crystal of copper complex of barbituric acid (CuB) (C8H10CuN4O9) is grown by conventional gel method. The crystal structure is orthorhombic with space group Fdd2 and has unit cell dimensions a = 11.6951(7) Å, b = 30.1113(19) Å, c = 7.1767(7) Å and α = β = γ = 90°. Analysis of the crystal by Hall–Williomson plot revealed the strain free nature of the grown crystals. Identification of the functional groups by FTIR and the study of thermal behaviour of the crystal by TGA/DTA were done.The optical band gap is determined as 1.57 eV from UV–visible absorption studies. The photoluminescence study provides information about the structural quality and purity of the crystal. Antibacterial studies of the sample revealed its medicinal applications. The high hardness value of the crystal is identified by Vickers micro hardness test. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.