The synthesis of unsymmetrically substituted 1,4-bis[(aminoalkyl)amino]anthracene-9,10-diones bearing one "mitoxantrone side arm" and another (aminoalkyl)amino moiety has been described. These unsymmetricalanthracene-9,10-diones exhibit cytotoxic activity against L1210 leukemia cells and antitumor activity against P388 leukemia in mice.