Chemical sensors based on micro/nanoelectromechanical systems (M/NEMS) offer many advantages. However, obtaining chemical selectivity in M/NEMS sensors using chemoselectiveinterfaces has been a longstanding challenge. Despite their many advantages, M/NEMS devices relying on chemoselective interfaces do not have sufficient chemical selectivity. Therefore, highly sensitive and selectivedetection and quantification of chemical molecules using real-time, miniature sensor platforms still remains as a crucial challenge. Incorporating photothermal/photoacousticspectroscopic techniques with M/NEMS using quantum cascade lasers (QCLs) can providethe chemical selectivity without sacrificing the sensitivity of the miniaturized sensing system. In this talk, I will present a recent progress on the development of multi-modal MEMS sensors for trace amount of explosive vapor detection.