High-resolution molecular spectroscopy for atmospheric and astrophysical applications is an important research activity within the Molecules in the Universe pole of LERMA. The activity helps investigating and understanding isotopic and nuclear spin effects. It also provides molecular spectroscopic data of wide use for the scientific community. Traceeability of these data has recently become key, requiring a very high level of control of our laser and frequency sources. For measurements in the mid-IR using tunable diode lasers, we therefore apply active stabilisation techniques, such as interferometer control or heterodyning with optical an frequency combs, that will be locked to the reference distributed by the REFIMEVE+ project. As part of the teaching activities, we also develop an atomic Cesium Cs clock.