In order to improve the relationship between the structure of bridging dinuclear complexes and their magnetic behavior, we did synthesize metal-organic [Co-2(mu(2)-H2O)(2)(mu(2)-SO4)(2)(C5H6N2)(4)]center dot 2.86(C2H6OS)center dot 2.88(C4H8O) 1. This dinuclear transition metal complex was characterized by infrared and UV-vis spectroscopy as well as single X-ray diffraction. The thermal and magnetic behavior of this complex was studied. Single crystal X-ray diffraction studies confirmed that 1 consists of discrete dinuclear cobalt entities and two free solvent molecules (DMSO, THF). The two cobalt ions are bridged by two water oxygen atoms and two bidentate sulfate groups to form a four bridged dinuclear core. The optical band gap was determined by diffuse reflection spectroscopy to 3.06 eV for an indirect forbidden transition. The magnetic measurements and DFT calculations suggest the presence of ferromagnetic exchange between Co(II) centers with a strong easy-axis anisotropy.