The crystal and molecular structures of the ligand bpenH2 (N,N′-bis(2′-pyridinecarboxamide)-1,2-ethane) and its deprotonated dimeric cobalt(III) complex fac-[Co2(bpen)3]·12H2O have been determined by single-crystal X-ray diffraction methods. Crystal data: (a) bpenH2, C14H14N4O2, orthorhombic, space group Pccn, a=9.638(1), b= 15.288(1), c = 8.684(1) Å, Z=4; (b) Co2(bpen)3· 12H2O, C42H60N12O18Co2, triclinic, space group P1, a = 11.128(3), b = 14.316(5), c = 16.466(4) Å, α= 92.02(2)°, β = 95.21(2)°, γ = 99.30(2)°, Z = 2. The structures were refined to R 0.034 and 0.053 for 1064 and 7748 independent reflexions, respectively. The bpenH2 molecule has a space group imposed centre of symmetry, with the amide group adopting a trans configuration in the closely planar picolinamide moiety. The cobalt complex is dimeric in which three bpen ligands, acting each as a bis(N2-bidentate), bridge the two metal atoms. Each cobalt atom is octahedral with CoNpy 1.944(3) and Co Nam 1.933(3) Å. The Co··Co separation is 5.493(1) Å. The symmetry of the dimeric molecule is D3 which is consistent with that indicated from solution NMR studies.