The properties of the monolayer of 5,11,17,23-tetra-tert-butyl-25,27-bis (2-aminoexthoxy)-26,28-dihydroxycalix[4]arene and its recognition capacity for 5'-AMP(-) and 5'-GMp(2-) at the air-water interface were investigated. pi-A isotherms and relaxation experiments indicate that it is able to form stable monolayers on pure water and two nucleotide-containing subphases. Moreover, the nucleotides in subphase are beneficial to the stability of its monolayer. The UV, CD, and FT-IR spectra of LB films from three subphases reveal that 5'-AMP(-) and 5'-GMP(2-) in subphase can be transferred onto the substrates along with the monolayer mainly via multiple hydrogen bonding and electrostatic interactions. The host-guest complexes of 5,11,17,23-tetra-tert-butyl-25,27-bis(2-aminoexthoxy)-26,28-dihydroxycalix[4]arene and nucleotides at the air-water interface were studied through the analysis of the X-ray photoelectron spectra data of LB films. The results indicate that 5'-AMP- and 5'-GMP2- were bound to the calix[4]arene monolayer in 1:1 and 1:2 molar ratio, respectively. Two intermolecular interaction patterns are proposed and the binding constants are estimated to be 1.4 +/-0.1 x 10(5) and 1.1 +/- 0.2 x 10(5) M-1 for 5'-AMP(-) and 5'-GMp(2-), respectively.