The structure and other physical properties of conjugated polymers are intensively studied in leading laboratories, due to the extremely interesting applicational perspectives of this class of materials. Among others, polyaniline and its derivatives are still in the center of interest of physics and chemistry polymers. Polyaniline in its protonated (conducting) form, like other polymers of this type, exhibits the X-ray diffraction patterns typical of semi-crystalline samples. The reasonable results concerning the crystalline structure of such low- ordered material can be obtained only by computer modelling of its structure. Choice of the solvent as well as the protonating agent has the great impact on the structural and electrical transport properties of the sample. For example, polyaniline films protonated with camphorsulfonic acid and casted from m-cresol exhibit the temperature dependence of electrical conductivity typical of metallic-like material. The structure of this polymer is still not known; however, we have obtained recently some interesting results in this field. Polyaniline may be significantly modified, in order to obtain a polymer characterized by expected properties. For example, poly(azomethines) or polyimines exhibit interesting catalytic properties, when they are doped with catalytically active species. In thsi work, the crystalline structures of unsubstituted poly(azomethine) and poly(azomethine) metoxysubstituted in the aromatic ring were determined by the X-ray diffraction method and the computer modelling. The diffraction patterns calculated for the models are almost identical as the crystalline components of the experimental diffraction patterns' also, the calculated densities are in good agreement with their experimental values. Such situation enables us to assume, that our models may be treated as the good approximation of the real crystalline structures of the polymers studied.