Abstract: A novel type of molecular cleft has been designed and synthesized from estrogen and approprite spacer groups such as xylylene or pyridine dimethylene. These receptor compounds 1a-d and 2a-d have been characterized by Mass spectra,¹H-NMR spectra,IR spectra and elemental analyses. The structures of the receptors are shown in scheme 1. Their molecular recognition properties for the aromatic amine and aromatic amino acids have been investigated by UV-visble spectrophotometric titration. The titration data were analyzed by using the Benesi-Hildebrand equation^[1].