On the basis of the present knowledge of the substrate recognition site of ABC transporter proteins and inspired by the structures of verapamil and pervilleine A, a new class of Pgp-mediated multidrug resistance (MDR) reverters has been designed and synthesized. The new compounds are flexible molecules carrying one or two basic nitrogen atoms flanked, at properly modulated distance, by two aromatic moieties. Most of the molecules studied possess MDR inhibitory activity on anthracycline-resistant erythroleukemia K 562 cells, showing a potency that is higher than that of the reference compound verapamil and, in a few cases (7, 12, 13,17, 20, 22, 28), is in the high nanomolar range. These compounds may be useful leads to develop new MDR reverting agents. In fact, the chemical structure of the class is fairly simple and can be implemented in a variety of ways that will allow the synthesis of new compounds that might be useful leads for the development of drugs to control Pgp-dependent MDR.