Among the C-C bonds, also the ones with sp Red carbon was reported to be highly reactive to Lewis bases, such as NH3, and, therefore, we exploited the possibility to use the red carbon thin films as sensing platform for amines. For the purpose, we chose a set of analogous alkylamines, mono-, di-, tri-ethyl and benzyl-, and an aromatic amine, aniline. In a simple setup we put 1 mL of the chosen amine in a 100 mL vessel (total volume 134 mL) and immediately sealed, after placing inside a 2.5 cm 2 red carbon thin film in another 5 ml vessel, to avoid direct contact with the liquid amine, as shown in the following (fig. ). In this way we assure that, if a reaction occurs, this happens only via gas-to-solid phase reaction. As shown in the following, the films after 24 hours exposure have a significantly different color, which can even be distinguished by naked eyes. As expected, the color change is stronger for primary amines than for higher and aromatic amines, after 24 hours; thus, the color change is not due to the higher vapor pressure of the amine, but to a chemical reaction between the red carbon films and the amine. Indeed, the boiling point of the ethylamine is 16.6°C, whereas benzylamine (which is as well a primary amine) is 185°C, at atmospheric pressure. A further proof of the chemical reaction is obtained by confirming the irreversibility of the color change by measuring the absorption spectrum after the exposure to ethylamine and after placing the sample in a vacuum over for 48 hours at 60°C (SI). other amines, with a strong bandgap blue-shift (from 2.10 to 2.52 eV) already after 30 seconds of exposure, which can be attributed to the higher vapor pressure and faster reaction kinetics of ethylamine. In all cases, after already one hour of exposure, we recorded a bandgap blue-shift, which is larger for the primary amines (2.78 eV for ethylamine, 2.61 eV for benzylamine) and the lowest for aniline (2.3 eV). This is possibly due to the higher pKa value (4.6), which speaks for different orders of magnitude higher acidity compared to the the other amines used here, and with comparable boiling point to benzylamine. In this way, we can rule out the predominant effect of the vapor pressure on the response, when vapor pressure equilibrium condition is reached. This is confirmed, by looking at the points after 24 and 48 hours of exposure. Indeed, ethylamine enables a very large bandgap blue shift of 1.14 eV (from 2.10 of bare red carbon to 3.24 eV after 48 hours) and 0.87 for benzylamine (2.97 eV after 48 hours). Concerning the other amines, the bandgap widening is similar after 48 hours, with a maximum total blue shift of about 0.4 to 0.5 eV. However, the shape of the sensing curve (Fig ) reveal a different kinetics, and behavior for each different amine, which would enable to distinguish them in a simple manner, particularly efficient for primary vs. secondary/tertiary and aromatic ones.