Optically transparent films of single chain ammonium amphiphiles having an azobenzene chromophore in the hydrophobic chain (CnAzoCmN(+)) were prepared by simple casting of their water or ethanol solutions. The UV-visible absorption spectrum of the azobenzene chromophore was strongly affected by the chemical structure of the amphiphile, especially on the chain length of the alkyl tail(n = 3-14) and the spacer group (m = 4-12), and is classified into six groups : absorption maximum of group I, 300-305 nm; group II, around 320 nm; groups III and IV, 345-355 nm; group V, 360-370 nm; group VI, 375 nm. Structural requirement of the group I is found to be m - n greater than or equal to 2. The amphiphiles with a long alkyl chain (n + m > 18) and structural relation of m - n less than or equal to 1 are comprised into the group III Amphiphiles with m = 8 and 7, except for the amphiphiles in groups I and II, are classified in group III. Groups ni and V consist of the amphiphiles with m = 4 and 6, respectively. Group VI consists of the series of amphiphiles with m = 5, except n = 3 and 4. X-ray diffraction experiments indicate that the cast films are composed of multiple stacked bilayers. Intensity distribution in the X-ray diffraction pattern of group V was very similar to group VI but different from groups I and II. Supposing a tilt molecular packing with ahead-to-tail chromophore orientation, the molecular axes inclines by 36 degrees and 26 degrees to the bilayer surface in groups V and VI, respectively. The molecules in groups I and II are supposed to be packed laterally in an antiparallel and mutually interdigitated fashion. Spectral difference of I and II is ascribed to full and partial overlapping of the azobenzene chromophores, respectively. A peculiar small void space under the bromide counterion is expected to be formed in the group I films if the spacer chain is longer than the alkyl tail (m - n > 2). Thermally induced structural transformation to V or VI was observed when the films of groups I and II were annealed above their phase transition temperatures.