The synthesis and characterization of aromatic rigid poly(urethanes) containing silicon and/or germanium in the main chain is described. These polymers were synthesized by condensation of aromatic diamines and the bis(chloroformates) of diphenols containing silicon or germanium as central atom and bonded to alkyl and aryl groups. The poly(urethanes) were characterized by FT-IR, H-1, C-13 and Si-29 NMR spectroscopy and the results were in according with the proposed structures. In addition, thermal characterizations were developed using DSC and TG techniques and the intrinsic viscosity were determined as evaluation of the molecular size. In all cases, the thermal properties were depending of the nature of the heteroatoms present in the repetitive unit.