The combination of a mcrocyclic cavity with o-diaminobenzene derivative offers a new redox-active and water-soluble ligand for barium that incorporates 12 potential donors. The chelator was synthesized in four steps from diaza-18-crown-6-ether and fully characterized in solution by cyclic voltammetry, UV-Visible and NMR spectroscopies in the presence of barium. The corresponding complex exhibits a 1:1 stoichiometry in solution whereas it crystallizes as 3:2 (M:L) as evidenced by X-ray diffraction studies. The high affinity constant for barium estimated by NMR and electronic absorption techniques in aqueous medium, makes this ligand a promising candidate for redox-induced barium release. (C) 2013 Elsevier Ltd. All rights reserved.