We present the syntheses, structural characterization, gas sorption, 12 uptake, and magnetic properties of a double-walled porous metal organic framework, [Co-3(II)(lac)(2)(pybz)(2)]center dot 3DMF (1.3DMF, purple, where pybz = 4-pyridyl benzoate, lac = D- and L-lactate) and of its post-synthetic modified (PSM) congeners, [Co-3(II)(lac)(2)(pybz)(2)]center dot xGuest (xGuest = 6MeOH, purple; 4.5EtOH, purple; 3PrOH, purple; 2C(6)H(6), purple; 2.71(2), black), [Co-3(II)(lac)(2)(pybz)(2)] (1, purple), [Co-3(II)(pybz)(2)(lac)(2)(H2O)(2)]center dot 7H(2)O (1a center dot 7H(2)O, green), and [(CoCo2II)-Co-III(pybz)(2)(lac)(2)(H2O)(2)]I center dot 2H(2)O.1.5DMSO (1b center dot I(-center dot)2H(2)O center dot 1.5DMSO, yellow, DMSO = dimethyl sulfoxide). Crystallography shows that the framework is not altered by the replacement of DMF by different solvents or by the removal of the solvent molecules during the single-crystal to single-crystal (SC-SC) transformations, while upon exchange with H2O or partial oxidation by molecular iodine, the crystallinity is affected. 1 absorbs N-2, H-2, CH4, CH3OH, C2H5OH, PrOH, C6H6, and ID but once it is in contact with H2O the absorption efficiency is drastically reduced. Upon PSM, the magnetism is transformed from a canted antiferromagnet (1.3DMF and 1.xGuest) to single-chain magnet (1), to a ferrimagnet (1a center dot 7H(2)O), and to a ferromagnet (1b center dot I-.2H(2)O center dot 1.5DMSO). Raman spectroscopy suggests the color change (purple to green 1a center dot 7H(2)O or yellow 1b center dot 1(-).2H(2)O.1.5DMSO) is associated with a change of geometry from a strained octahedron due to the very acute chelating angle (similar to 60 degrees) of the lactate of a cobalt center to a regular octahedron with a monodentate carboxylate and one H2O. The magnetic transformation is explained by the different interchain exchanges (I), antiferromagnetic for 1 center dot 3DMF and 1.xSolvent (J' < 0), SCM for 1 (J' verge to 0), and ferromagnetic for 1a center dot 7H(2)O (J' > 0), between homometal topological ferrimagnetic chains (two octahedral and one tetrahedral Co-II ions) connected by the double walls of pybz at 13.3 angstrom (shortest Co center dot center dot center dot Co). For 1b center dot I(-center dot)2H(2)O center dot 1.5DMSO the moment of the tetrahedral site is turned off, thus stabilizing a ferromagnetic state (1 > 0). The present stabilization of four magnetic ground states is unique in the field of metal organic frameworks as well as the electrical conductivity of 1.2.7I8(2).