Molecular recognition of naphthalene derivatives by amphiphilic beta-cyclodextrins (CDs) monolayers at the air-water interface has been investigated, From monolayer behaviours of the beta-CDs including the guest molecules and some optical properties of their LB films, it has been found that the recognition and orientation of the guest molecules depend upon not only the coulombic interaction between the host and the guest molecules but also the substituted positions in the naphthalene ring.