Novel molecular functions are conveniently designed by taking advantage of the self-assembling properties of monolayers and bilayers. Some surface monolayers bind guest molecules efficiently by complementary hydrogen bonding. In particular, a long-chain derivative of Kemp's acid forms a cyclic dimer species at the air-water interface and binds nitrogen aromatics and amino acids specifically. The self-assembling property of the aqueous bilayer leads to formation of self-supporting cast films with regular multilayer structures. Certain guest molecules are incorporated into bilayers in ways that reflect the molecular assembly of the matrix bilayer. The orientation of negatively charged porphyrins in matrices of ammonium multi-bilayers is determined by optimized electrostatic interactions. Molecular orientations of myoglobin and other heme proteins in bilayers are controlled in a similar manner. Alkoxysilanes are incorporated regularly into the interbilayer space of the cast film and condensed to form silicate layers. Multilayered ultrathin silicate films are obtainable upon extraction of organic matrices.