The effects of distributions of dislocations, disclinations and charge admixtures on the structural transformations in thin LC films are discussed in the framework of the phenomenological approach. The quasiequilibrium spatial modulation of polarization in the ferroelectric LC after or under the external field actions is described as the result of modulated distributions of free charges and disclinations. The electrostatically induced growth of spiral domains in Langmuir monolayers at the air-water interface is described as the result of modulated distributions of the tilt angle and free charges in the chiral polarized thin film. The chiral smectic A* phase is described as the periodic distribution of dislocation walls and disclination loops in the layered system.