We have prepared several organometallic systems whose structures are closely analogous to that of tamoxifen, the drug used in the treatment of hormone-dependent breast cancers, but which now possess two basic aminoalkyl chains: O(CH(2))(3)NMe(2). Despite the absence of a phenolic functionality, these ferrocenyl compounds 3, 4 and their organic analogue 5 recognize the estrogen receptor but in addition exhibit strong antiproliferative effects on hormone-dependent breast cancer cells (MCF-7), and also on hormone-independent ones (MDA-MB-231) with, in this case, an IC(50) value of about 0.4 mu M. The ferrocenyl moiety does not create a major effect here compared to a purely organic aromatic group. On the other hand, the presence within the molecule of two vicinal basic entities, potentially allowing complexation to metal ions such as Zn(2+), could perhaps be the key to the antiproliferative effectiveness of this series which operates via a different mechanism to that of hydroxytamoxifen 1 and hydroxyferrocifen 2. The behaviour of these new species is discussed. They possess the distinctive feature of combining a strong antiproliferative effect with intense antibacterial and antifungal activity.