So far, sensors functionalized with MOFs or related adsorbents have exclusively relied on equilibrium adsorption to achieve selectivity. Nevertheless, in crystalline nanoporous materials, particularly those with narrow pore windows, differences in adsorption kinetics can be much more pronounced than differences in equilibrium uptake for similar adsorbates. Even molecules with comparable equilibrium uptakes can have diffusivities that differ by orders of magnitude, especially when they vary slightly in size . In this work, inspired by the role of mass transfer in the olfactory mucosa, we introduce the kinetic selectivity achievable in nanoporous crystals for the first time into the domain of chemical sensors. The novel measurement concept paves the way for designing highly selective sensors that can be adapted to meet the demands of specific use cases.