Résumé : Diorganotin derivatives of dicarboxylic acids, including diethyltin propene‐1,3‐dicarboxylate, diethyltin homophthalate, and di‐n‐butyltin tetrafluorophthalate, were tested in vitro against two human tumor cell lines, MCF‐7, a mammary tumor, and WiDr, a colon carcinoma. Most of these display lower inhibition doses ID50 than cis‐platin. The synthesis and characterization of the last three compounds by Mössbauer spectroscopy, 1H, 13C and/or 119Sn NMR and mass spectrometry, are also presented. Copyright © 1992 VCH Publishers, Inc.