A berkelium(III) mellitate, Bk₂[C₆(CO₂)₆](H₂O)₈·2H₂O, was synthesized and rapidly crystallized by reacting mellitic acid, C₆(CO₂H)₆, and BkBr₃·nH₂O in an aqueous medium. Single crystal X-ray diffraction shows that the compound crystallizes as a three-dimensional framework isostructural with Pu(III), Am(III), and Cm(III) mellitates. UV-vis-NIR spectroscopic studies as a function of pressure were performed using a diamond anvil cell and show that the 5f → 5f transitions of Bk³⁺ display enhanced hypsochromic shifting when compared to other An(III) mellitates.