A new single-chain amphiphile 5-(dodecyloxy)-1-((6-(trimethylammonio)hexyl)oxy)napthalene (C(12)Naph(1,5)(C6N+) can be deposited as LB films onto substrates by using the Langmuir-Blodgett technique with the subphase of aqueous sodium dextran sulfate (SDS) solution. Steady-state fluorescence spectra of the LB films were recorded. The differences in the spectra of the films from the aqueous and organic solutions of the amphiphile are mainly ascribed to the formation of naphthalene excimers, and investigations on the dependence of the relative content of naphthalene excimers in the films upon aggregation state indicate that the excimer formation is promoted with increasing the close packing density of the molecules. The molecular orientation in the LB films was studied with the application of the fluorescence polarization technique, and the results revealed intuitively that the film-forming molecules are aligned with their naphthalene chromophores close to the film normal with the direction of maximal probabilities of the transition moments tilting in certain angle ranges from the normal. It was found that the tilt orientation of naphthalene chromophores is of advantage to excimer formation.