Lead based oxides are wildly used in material science in order to obtain non-centrosymmetric structures that eventually lead to polar or piezoelectric distortion, which coupled with magnetic cation, may induce multiferroicity. In this proposal we suggest a detailed crystallographic study of the magnetic and crystal structures of two compounds in the Pb-Mn-Re-O system: the piezoelectric and 1D magnet Pb4MnRe2O13 and the double perovskite system Pb2MnReO6 that shows a commensurate nuclear modulation at room temperature and ferrimagnetism below 100 K. The proposed experiment will provides high quality diffraction data that will allow the refinement of the complex crystallographic structure of these two compounds as well as the low temperature magnetic ordering. The obtained results will be used to relate the physical properties with the nuclear and magnetic structures.