The electrochemical behavior of the new ionophore N,N-di(methylenecarboxyethoxy) 4,10-diaza-2,3,11,12-dibenzo-18-crown-6 (DIAZ18C6) at the water vertical bar 1,2-dichloroethane (1,2-dichloroethane = 1,2-DCE) interface was studied by means of cyclic and square wave voltammetry techniques. DIAZ18C6 was able to transfer Pb2+, Zn2+, and Cd2+ across the interface and stoichiometries of 1:1 (Pb2+,Zn-2) and 1:2 (Cd2+) were found. DIAZ18C6 is highly soluble in 1,2-DCE; this mean that an interfacial complex formation takes place at the interface. These studies showed that a facilitated transfer of Pb2+ requires less energy to be transferred from water to the organic phase than the facilitated transfer of Zn2+ and Cd2+ across the water vertical bar 1,2-DCE interface. As a consequence, this ligand showed selectivity for Pb2+ over the other studied cations. The present work could contribute to a better understanding of the transfer of heavy metal in a biological cell or of selective metal extraction. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3467803] All rights reserved.