Metal-organic frameworks (MOF) are nanoporous materials made of metal ion centers coordinated by organic linkers to form 3D-structures 1,2 that have attracted much attention for catalysis, 3-6 sensing 6,7 and gas capture and separation. In these materials, efficient and selective gas adsorption can be achieved due to the large internal surface area and the high affinity of the metal centers with certain gas molecules. The presence of coordinatively unsaturated metal centers, also called open-metal sites, has resulted in large gas uptake at low pressure owing to the formation of selectively strong coordination bonds between the MOF and the guest molecules. Recently, a cooperative carbon monoxide adsorption mechanism via spin-transition has been reported in MOFs exhibiting open-metal site Fe centers. Exceptionally large working capacities and low regeneration energies were obtained as a result of a step-shaped isotherm resulting from a cooperative change in the gas binding properties upon electronic transition. The spin-state transition from high spin (HS) to low spin (LS) occurred as a function of the CO partial pressure, as a result of the strong ligand field induced by CO upon adsorption. Once the HS→LS is triggered at all Fe centers, the uptake is shown to increase abruptly as a consequence of the significantly larger CO binding energy expected at LS compared to HS. The change in the affinity of the adsorbent material for the gas reported by Long and coworkers arises from the change in the occupation of the antibonding d z 2 . This idea had already been shown in general terms by some of the present authors using ab initio electronic structure calculations and will be leveraged here to demonstrate the feasibility of a more general spin-crossover induced gas release. In point of fact, the efficient CO adsorption-desorption process discussed above relies on the step-shaped adsorption isotherms that may be possible only for large gas-induced ligand field splittings such as for CO, and thus cannot be applied for most gases. As an alternative to this cooperative adsorption mechanism, these concepts can be translated into an efficient and more general spin crossover-assisted desorption process whenever by applying, ideally, a small temperature swing to the material, the affinity between the gas and the material decreases substantially as a result of the change in the spin state of the transition metal cation acting as adsorbing site.