The layering transitions of mesomorphic poly[bis (2,2,3,3-tetrafluoropropoxy)phosphazene] induced by compression were found to result in the formation of stable multilayers directly at the air/water interface. This phenomenon is discussed with particular emphasis on its in situ structural characterization by Brewster angle microscopy, infrared spectroscopy, synchrotron grazing incidence X-ray diffraction, and X-ray reflectivity data. Compression of Langmuir monolayer is followed by layer-by-layer growth manifested by pronounced steps in the pressure/area isotherm. Grazing incidence X-ray diffraction reveals only one diffraction peak for the monolayer as well as for multilayers, which corresponds to an interchain spacing d = 12.3 angstrom. The in-plane correlation length xi(xy) reaches an impressive 345 angstrom for the uncompressed monolayer and 470 angstrom for the tetralayer, implying a certain mesoscale order similar to a quasi-long-range one. After formation of the four-layer thick film the transition into a 3D crystalline triclinic phase with a = 13.19 angstrom, b = 11.42 angstrom, c = 4.83 angstrom, alpha = 90 degrees, beta = 102 degrees, and gamma = 116 degrees is observed.