The Infrared Laser Center of Orsay (CLIO) is a unique infrared user facility in France, comprising an electron accelerator that produces an energy beam ranging from 10 to 45 MeV and a Free Electron Laser (FEL) that is continuously tunable between 5 and 150 μm. This FEL, along with commercial OPO/OPA lasers (Optical Parametric Oscillator/Optical Parametric Amplifier), is coupled with several ion trap mass spectrometers from the SMAS platform (Mass Spectrometry, Analysis, and Spectroscopies) to study the structure of ions in the gas phase. Under an infrared laser pulse, the resonant absorption of multiple photons induces ion fragmentation, which is detected via mass spectrometry and serves as an absorption probe. This unique IRMPD (Infrared Multiple Photon Dissociation) spectroscopy technique offers researchers the selectivity, versatility, and sensitivity of mass spectrometry. By varying photon energy across a broad range in the IR region, it also allows researchers to record the IR spectrum of mass-selected species over a full spectral range of 2.5 to 10 µm. The SMAS/CLIO platform and its high-field FT-ICR mass spectrometer are part of the CNRS national Infranalytics infrastructure and one of eight operando/prototyping platforms within the PEPR LUMA (Priority Research Program and Equipment on Light-Matter Interaction).