Ellipticine and some of its derivatives are organic molecules with intense antitumor activity. In this work we report a semiempirical study on the electronic structure of ellipticine and some derivatives. Geometrical and spectroscopic aspects were investigated through the use of the well-known PM3 (Parametric Method 3) and ZINDO (Zerner's Intermediate Neglect of Differential Overlap) methods. Comparing PM3 and previously reported AM1 (Austin Method One) results, we found out that overall PM3 results are better. The ZINDO simulated absorption spectra compare well to the available experimental data. We have observed a very simple correlation between the dipole moment value (DM) and the antitumor activity. These results suggest a way to improve and design new antitumor ellipticine derivatives, as well as, to select promising molecules from untested groups. (C) 1999 Elsevier Science B.V. All rights reserved.46541700219229