In this work, we report the synthesis and crystal structure of two 1D–coordination polymers and one mononuclear complex based on pyrazine-2,3-dicarboxylic acid (H2pyz-2,3-dc), pyridine-2,3-dicarboxylic acid (H2py-2,3-dc) and pyridine-2,6- dicarboxylic acid (H2py-2,6-dc) ligands namely {[H2-atz]2[Cu(pyz-2,3-dc)2]}n (2-atz=2-aminothiazole) (1), {[H2- atz]2[Cu(py-2,3-dc)2]}n (2) and [Cu(py-2,6-dc)(2-atz)(H2O)] (3). Single crystal X-ray diffraction analyses displayed that utilizing different structural isomers (2,3- and 2,6-) of dicarboxylic acid lead to geometrical and structural diversity. Two coordination polymers have a distorted octahedral geometry, in which the (pyz-2,3-dc)2– and (py-2,3-dc)2– moieties act as tridentate bridging ligands in 1 and 2 so that 1D chains are in a similar fashion, while complex 3 exhibits a 3D supramolecular network with square pyramidal geometry. Moreover, to investigate the influence of particle size on physical properties such as magnetic behavior and thermal stability, nano–structures of mentioned polymers were synthesized by sonochemical method and characterized by scanning electron microscopy (SEM), elemental analyses, powder X- ray diffraction (PXRD), infrared spectroscopy (IR), and thermogravimetric (TGA) analyses. The investigation of magnetic properties of compounds 1, 2 and corresponding nano structures indicate that there are weak antiferromagnetic interactions between the CuII ions in the temperature range of 1.8 - 300 K.

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