The mid-infrared (MIR) region is emerging as the favourite wavelength band for a number of applications, including high sensitivity trace detection, chemical emission monitoring, process control, and biological sensing applications. An efficient way to get precise and reliable information is to rely on spectroscopic analysis and, among the existing technologies, Tunable Diode Laser Spectroscopy (TDLS) has been identified to be the most attractive solution due to the unique adsorption spectrum of chemicals, allowing their unambiguous detection. In the MIR region, the availability of Quantum Cascade Lasers (QCL) covering a broad portion of the spectral range (MIR, 3-12 µm), where many chemicals of interest for Safety & Security have their strongest absorption lines, has recently pushed forward the commercialisation of TDLS-based detection units.Further technology advancements are still needed in the TDLS and QCL domains, the crucial bottlenecks being the range of tuneability, the footprint, power consumption & wallplug efficiency. Besides high cost and poor versatility, these limitations set a barrier for the realisation of powerful versatile detection units. To address these issues, MIRIFISENS will bring major technological advancements in the field of miniaturisation, process development, heterogeneous integration and co-integration of MOEMS functionalities.The project will exploit state-of-the-art micro and nano-fabrication techniques. The major technologic achievements proposed will address the issues of sensitivity & selectivity, multi-gas capabilities, compactness, efficiency and cost effectiveness as specified by a number of selected Safety & Security applications. These achievements will be tested and validated for these applications. MIRIFISENS will deliver a new class of sensors with superior tuneability, better portability and extended detection capabilities, changing radically the current landscape of MIR chemical sensing spectroscopy.