Two hexagonal-perovskite-structure oxides, 21R Ba7Fe5Ge2O20 and 12H Ba6Fe3Ge3O17, were obtained by synthesis with a high-pressure and high-temperature technique. The Fe-containing hexagonal-perovskite-structure units are sandwiched by nonmagnetic GeO4 tetrahedral layers in the structures, and thus both compounds show two-dimensional ferrimagnetic behaviors due to intra- and interunit magnetic interactions. 21R Ba7Fe5Ge2O20 has the ionic formula Ba(7)Fe1(2)(3+)Fe2(4+)Fe3(2)(4+)Ge4(2)(4+)O(20) at room temperature, and unusually high valence Fe4+ in the trimers undergoes charge disproportionation, Fe2(4+) + 2Fe3(4+) -> Fe-2((4+2 delta)+) + 2Fe3((4-delta)+), at low temperatures. In contrast, 12H Ba6Fe3Ge3O17 with ionic formula Ba(6)Fe1(2)(3+)(Fe2(0.5)(4+) Ge2(0.5)(4+))(2)Ge3(2)(4+)O(17) does not show a charge transition.