Two cobalt(II) compounds [Co(2,2'-bipy)(H 2 O) 2 (SO 4 )] n (1) and [Co 2 (2,2'-bipy) 2 (btec)(H 2 O) 6 ]·2H 2 O (2) (2,2'-bipy = 2,2'-bipyridine, H 4 btec = 1,2,4,5-benzenetetracarboxylic acid), have been simultaneously synthesized by a one-pot slow solvent evaporation reaction. Their structures were determined by single-crystal X-ray diffraction and further characterized by X-ray powder diffraction (XRPD), IR, elemental and thermogravimetric analysis (TGA). The structural analysis reveals that compound 1 exhibits an infinite 1D chain structure with the octahedral Co(II) centers bridging by the tetrahedral µ 2 -SO 4 2− ligands, while compound 2 possesses a dinuclear Co 2 (2,2'-bipy) 2 (btec)(H 2 O) 6 unit and the two adjacent octahedral Co(II) ions are linked by the bismonodentately coordinated btec ligand. Additionally, compound 2 exhibits blue fluorescent emission in the solid state at room temperature.