In the title monomer, [Cu(NO₃)₂(C₂₄H₁₆N₂)₂], the copper(II) cation is eight-coordinate within an octahedral-like polyhedron. The coordination polyhedron is formed by two chelating diphenylphenanthroline groups that define the highly distorted CuN₄ equatorial plane and two weakly bound bidentate (chelating) nitrate groups in the apical or axial positions. The complex crystallizes in the monoclinic space group C2/c; a twofold axis passes through the copper(II) cation and bisects the two nitrate ligands. This gives the molecule C₂ point-group symmetry, rendering only half of the molecule independent.