The [Co2(tbb)CU]-4DMF complex, where tbb is /w^o-l,2,3,4-tetra(lH-bcnzoft/]imidazol-2-yl)butanc, is synthesized and characterized by single crystal X-ray diffraction. For the complex: C44H54C02C14N12O4, M,.~ 1074.65, monoclinic crystal system, space group P2\/n, a = 9.2350(13) A, /> = 11.3566(15) А, с = 23.879(3) A, p = 90.547(2)°, V= 2504.3(6) A3, Z= 2, Д. = 1.425 g/cm3, A. = 0.71073 A, ц(МоКы) = 0.929 mm l, F(000)=11I2, 5=1.047, /? = = 0.0765, and w/? = 0.2110 for 13668 observed reflections with /> 2a(l). It is a neutral dinu-clear complex. One m^vo-l,2,3,4-tctra(lH-bcnzo[J]imidazol-2-yl)butanc coordinates two co-balt(II) ions. Each cobalt(II) ion is formed by two tbb nitrogen atoms and two chloride ions. The antiproliferative activities of the complex are screened by MTT assay against Ecal09 cancer cells. The complex exhibits inhibition on the growth of Ecal09 cancer cells with IC50 of 22.116.7 цМ after 48 h treatment. The cobalt complex has potential application in treatment of Ecal09 cancer. CCDC 1015791.