Three crescent aromatic oligoamides 1-3 with their backbones rigidified by intramolecular hydrogen bonds were designed and synthesized. The liquid-liquid extraction by these compounds has been investigated using UV-vis spectrometry towards Pb2+ picrate and some transition metal picrates including Ag+, Hg2+, Cd2+, Zn2+, Cu2+, Co2+, Ni2+ salts. The results revealed higher selectivity and efficiency towards Hg2+ over other metal cations; pentameric ligand 1 with six oxygen donor atoms provided the highest extractability of 83.3%, while dimeric ligand 3 extracted almost exclusively Hg2+. The stoichiometry of the extracted complex between ligand 1 and Hg2+, and the extraction constant (log K-ex) were determined in solvent extraction. (C) 2012 Elsevier B.V. All rights reserved.