The geometry of the ground (S0) state of M comprising two water molecules around the carbonyl and hydroxyl group (Figure ) has been optimized at density functional theory (DFT) level as detailed in the computational methodology section. The absorption spectrum obtained at time-dependent-DFT (TD-DFT) level around the Franck-Condon region is also reported in Supplementary Information (SI) and correlates well with the experimental results, showing only a slight to moderate shift compared to those of the chromophore in vacuo. As also confirmed by the Natural Transition Orbitals (NTO) reported in SI the two lowest singlet excited state can be assigned as pp* and np* for S1 and S2, respectively. Consequently, the lowest singlet state is brighter, and can, therefore, be considered as the most photochemically relevant. As shown in the Jablonski diagram reported in Figure , at Franck-Condon, the first singlet excited state of M lies at 4.046 eV from the ground state and the three lowest triplet state are positioned at lower energies, namely 2.448 eV, 3.604 eV, and 4.015 eV for T1,T2 and T3. Interestingly, at Franck-Condon S1 is quasi-degenerate with T3. At M S1 equilibrium geometry the first singlet excited state is stabilized by 0.2 eV and the quasi-degeneracy between S1 and T3 is lifted, since the triplet state overcomes S1 by 0.3 eV. The two lower triplet states are instead located at 2.201 eV and 3.621 eV for T1 and T2, respectively. The opening of a non-negligible singlet-triplet gap at the S1 equilibrium geometry may be seen as a first hint corroborating the role of water in quenching, or at least slowering, ISC. Importantly, a consistent reorganization of the microhydration network can be observed at S1 equilibrium geometry, involving in particular the rotation of the water molecule directly interacting with the hydroxyl moiety and a less pronounced, yet non-negligible reorientation of the carbonylinteracting solvent molecule. Concerning the energy levels at T1 equilibrium geometry, we may observe a reinstated quasi-degeneracy between S1 and T2, while T3 lies at 4.574 eV and T1 at 2.064 eV. These results would globally suggest that a possible channel leading to ISC should involve S1 and T2. Yet, the spin orbit coupling (SOC) element betweent these two states are quite modest amounting to 2.11 cm -1 at the S1 equilibrium geometry as shown in SI.