Metal-organic frameworks (MOFs) have shown great promise for sensing of dangerous chemicals, including environmental toxins, nerve agents and explosives. However, challenges remain, such as the sensing of larger analytes and the discrimination between similar analytes at different concentrations. Herein we present the synthesis and development of a new, large-pore MOF for explosives sensing, and demonstrate its excellent sensitivity against a range of relevant explosive compounds including trinitrotoluene (TNT) and pentaerythritol tetranitrate (PETN). We have developed an improved, thorough methodology to eliminate common sources of error in our sensing protocol. We then combine this new MOF with two others as part of a three-MOF array for fluorescent sensing and discrimination of five explosives. This sensor works at part-permillion concentrations and importantly, can discriminate explosives with high accuracy without reference to their concentration.