A novel amphiphilic ferrocene derivative (P) containing barbituric acid was designed and synthesized. It has a pi-donor-switch-acceptor structure, in which the N,N-dioctadecylaniline unit serves as the electron donor, the ferrocene moiety as the switch, and the barbituric acid unit as the electron acceptor. The non-linear optical experiments show the lipid P displays efficient optical second harmonic, generation (SHG) with a molecular hyperpolarizability (beta) as high as 1.8 x 10(-28) e.s.u. The lipid P alone is unable to form a high quality monolayer at the gas-water interface. The molecular recognition of the lipid P and its complementary substrate-melamine derivative (M), at the gas-water interface, may significantly improve the monolayer formation of the lipid P. The improvement of the monolayer has been found to exhibit a temperature-dependent effect : at about 24.5 degrees C it reaches the optimum.