Here, we report two three-dimensional metal-organic frameworks of formula [Co-2(4-ptz)(2)(bpp)(N-3)(2)](n) (1) and [Co-3(OH)(2)(bdt)(2)(bpp)(2)(H2O)(2)](n) (2), which were synthesized by hydrothermal reaction from the respective tetrazole ligand (5-(4-pyridyl)tetrazole (4-H-ptz) for 1 and 5,5'-(1,4-phenylene)bis(1-H-tetrazole) (H(2)bdt) for 2), long and flexible pyridyl-containing ligand 1,3-bi(4-pyridyl)propane (bpp), NaN3, and CoCl2. Both 1 and 2 consist of well-isolated one-dimensional cobalt(II) alternating chains further linked by the bpp and/or the tetrazole ligand, while their chain structures are totally different. The chains of I are formed by Co2+ ions bridged by single mu-EE-N-3 and triple (mu-EO-N-3)(mu-tetrazole)(2) alternately, whereas the Co2+ ions are bridged by mu(3)-OH to form Co-3(OH)(2) chains in compound 2. Magnetic measurements demonstrate that compound 1 contains an alternating antiferromagnetic (AF)/ferromagnetic (FM) ferrimagnetic chain, while compound 2 exhibits the coexistence of spin canting, slow magnetic dynamics, and finite-size effect, with alternating AF/AF/FM ferrimagnetic chains.