Molecular recognition properties of novel receptors1～6 for aniline, p-methoxyaniline and p-nitroaniline have been investigated by UV-vis spectroscopic titration, which indicates that the supramolecular complexes consist of 1:1 host and guest molecules. The main driving forces are the multiple hydrogen bonding and π-π stacking interaction between host and guest molecules. The molecular recognition ability is discussed from the viewpoint of the size/shape-fit and geometrical complementary relationship. A computer-aided study and ¹H NMR spectroscopy have been employed to elucidate the binding behavior of these molecular clefts.

Key words: molecular recognition, cholic acid, molecular cleft, ¹H NMR, UV-vis spectral titration