X ray crystallography is an emergence which has become very useful in many fields of study. Particularly in medicine, being able to determine the defining structures of specific atoms within a molecule and then changing that structure to obtain different functions can be particularly useful. We deal with characterizing and studying the properties of rare earth inorganic complexes with organic ligands. Both mono and polycrystalline techniques are useful to determine not only the structure and bonds that form within these molecules. We were able to synthesize and determine the structure of two isomorphous cobalt(II) complexes: 1,2-di-4-pyridylethane analogue and poly[[diaqua-u-2,5-dicarboxybenzene-1,4-dicarboxylato-u-1,2-di-4-pyridylethene-cobalt(II)]1,2-di-4-pyridylethene solvate].