Octadecylaminodihydroxysalicylaldehyde, an amphiphilic schiff base has been prepared and the behaviour of both the stable Langmuir films at air/water interface as well as the Langmuir-Blodgett (LB) films have been studied using photoelastic-modulated Fourier transform infrared (PEM-FTIR), ellipsometry at Brewster angle and transmission electron microscopy (TEM). The results indicate that to accommodate the cross-sectional mismatch between the tail and the head group regions, the chains tilt allowing the film to organise in a stable arrangement. It is also seen that the competition between the packing of the head groups and the long alkyl chains has important consequences for the microscopic structure of the LB films and the size of the ordered domains.