Abstract: A new metal-organic complex Co(C12H10N4)2(H2O)4·2C4H3O4n (where C12H10N4,C4H3O4 represents the 4-bpdb=(1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene,fumaric acid,respectively) has been hydrothermally synthesized,and was characterized by IR,elemental analysis and Single-crystal X-ray diffraction techniques,revealing that the structure of the synthesized complex belongs to triclinic system with space group p-1.The cell parameters are as follows:a=0.62895(3)nm,b=0.70107(3)nm,c=2.08838(10)nm,β=92.502(2)°,γ=113.331(2)°,V=844.038(7)nm3,Dc=1.537mg/m3,Mr=781.60,Z=1,μ=0.586mm-1,F(000)=405,R1=0.0299,wR2=0.0916.The central ion Co (Ⅱ) is coordinated with two nitrogen atoms from two 4-bpdb ligands and four oxygen atoms from four water molecules.The mononuclear molecules are interlinked by not only hydrogen atoms between the coordinated water molecules and uncoordinated fumaric acid,but also-stacking interactions of wR2=0.0916. Each Co(Ⅱ) atom is coordinated by two nitrogen atoms from two 4-bpdb ligands and four oxygen atoms from four water molecules.The mononuclear molecules are interlinked by not only hydrogen atoms aromatic ring,forming a 2D supramolecular network.The magnetic susceptibility measurement investigation suggested an antiferromagnetic coupling between the Co(Ⅱ) ions in the complex (Tθ=-2.99K).CCDC:1409869.