Two new isostructural coordination polymers, [Zn3(Oba)4][Me2NH2)2]·6DMF·3H2O (1) and [Cd3(Oba)4][Me2NH2)2]·2DMF·2H2O (2), were prepared using a non-linear dicarboxylate ligand, 4,4′-oxybis(benzoic acid) (H2oba) and analysed by X-ray crystallography. Single-crystal X-ray data show that these compounds are two-dimensional coordination polymers. In 1 individual planes are connected through CH…O (2.588 Å) secondary interactions and form 3D supramulecular networks. Nanoplates of these two new coordination polymers were sonochemically synthesized by varying sonication time and power of irradiation. Upon increasing power of irradiation uniform nanoplates with reduced thickness have been obtained. Also these coordination polymers were used as precursors for preparation of ZnO and CdO nanostructures by calcination at 550 °C.