Aniline is an important molecule from a fundamental point of view because it is the prototype of aromatic amines, but it is also important for industry due to its highly exploited conducting polymer in the materials engineering field. High pressure and temperature studies on the chemical stability of aniline are mandatory to figure out how to trigger aniline’s reactivity in reduced space for a possible practical exploitation of high pressure in the synthesis of novel materials, such as highly ordered polyaniline. Synchrotron X-ray diffraction (XRD) experiments allowed the aniline’s equation of state to be expanded up to 16.3 GPa. UV–vis absorption and Fourier transformed IR (FTIR) experiments at different pressure and temperature showed an anomalous chemical stability of aniline with respect to other aromatic systems, likely due to the hydrogen bonds arrangement. Reactivity has been laser-induced showing, for short irradiation, the formation of a limited amount of saturated chain-like structures that collapse, once further irradiated, into a 3D amorphous extended network.