The asymmetric unit of the title compound, C(18)H(18)N(2)O(2), consists of two independent mol-ecules, each of which is located about a center of inversion. The mol-ecules are not planar, showing dihedral angles of 55.84 (9) and 54.10 (8)° between the piperazinedione and the aromatic rings. The piperazine N atoms exhibit a planar configuration. The crystal packing is stabilized by inter-molecular C-H⋯O hydrogen bonds.