Two new luminescent metal-organic frameworks (LMOFs) were synthesized and examined for use as sensory materials. Very fast and effective sensing of RDX was achieved by vapor detection of a cyclic ketone used as a solvent in the production of plastic explosives. The effects of porosity and electronic structure of the LMOFs on their sensing performance were evaluated. We demonstrate that the optimization of these two factors of an LMOF can significantly improve its sensitivity and selectivity. We also elucidate the importance of both electron and energy transfer processes on the fluorescence response of a sensory material.