In Chem. Sci. 11 (2020) 516 and Chem. Sci. 11 (2020) 9162, I capitalize on the knowledge of the previous work studying the functionalization of gold surfaces with derivatives of the perchlorotriphenylmethyl (PTM) radical. PTM is a very persistent and stable radical that shows a long coherence time at room temperature, being a strong potential candidate for quantum technologies. I used a ferrocene functionalized PTM derivative with an alkyne termination (Figure ) that spontaneously covalently attaches to the gold substrate. The ferrocene functionalization makes the molecules interesting for current rectification, as seen in radical self-assembled monolayers (SAMs) incorporating ferrocene acting as a redoxactive moiety. I investigated also the formation of SAMs obtained by using on-surface chemistry. While the chemical stability of the PTM radical was well-known, PTM is considered an inert radical, here I show that the radical monolayers have unprecedented stability under ambient conditions and aggressive X-ray exposure. Extremely prolonged X-ray exposure indicates a dynamic nature of the radical-Au complex, analogously to the case of thiolates-Au surfaces. Although further investigations on the long-term aging pattern of the PTM radical-based layers also depending on different parameters, such as temperature and visible light, are necessary, the results point out that carbon absorption from ambient plays a major role when the monolayer is exposed to air for a long time. The PTM radical and its derivatives form monolayers with unprecedented stability properties, confirming that these systems are suitable candidates for market-oriented applications.