The research activity of the Supermolecules Project, which is administered by the Research Development Corporation of Japan, is described. This Japan-France collaborative project is made of three research groups at Kurume Research Park in Kyushu, Keihanna Research Park in Kyoto, and Université Louis Pasteur in Strasbourg. Major research topics of the Kurume group are molecular recognition by interfacial hydrogen bonding, formation of molecular patterns, and layer-by-layer adsorption. In the first topic, it was found that complementary hydrogen bonding provided efficient host-guest interactions at the macroscopic and mesoscopic interfaces. In the same vein, aqueous dipeptides are selectively bound to monolayers bearing peptide chains. In the second field, designed arrangement of component molecules in monolayers was realized through either specific interaction with aqueous templates or complementary hydrogen bonding among monolayer components. Preparation of ultrathin films by alternate adsorption was extended from the original use of linear polyelectrolytes by other groups to biopolymers and inorganic macroions. The extension to small molecules also expanded the usefulness of this technique.