A cleft-shaped receptor 1 was synthesized and its anion binding properties have been investigated. Receptor 1 can selectively recognize fluoride ion by naked-eye color change and UV-vis spectral changes in aqueous-acetonitrile solvent. The single crystal X-ray analysis of 1 with fluoride ion shows that there are two types of fluoride ions in the unit cell, one of which is pseudoencapsulated within the cleft-shaped cavity and the other type forms a dimer through [F 2(H 2O) 3] 2-fluoride- water cluster. © 2012 The Royal Society of Chemistry.