Fourier transform transmission infrared and W-Vis absorption spectra have been measured for a photochromic behavior of a novel amphiphile 2,4-dihydroxy-N-octadecylbenzylideneamin bearing Schiff base moiety as polar head in the close-packing LB films on solid supports. Measurement of pi -A isotherm show that 2,4-dihydroxy N-octadecylbenzylideneamine formed a stable and condensed monolayer at air-water interface. The built-up multilayer was found to exhibit photochromic behavior upon irradiation of 365 nm Light. The configuration rearrangement of the pi -electrons induced a large spectral change.