The initial equilibrium geometries for the GS, as well as S1 and T1 states of enol CURC have been obtained at DFT level using the wb97XD 27 functional together with the Pople double-z 6-31+G(d,p) basis set, coherently with what has been presented in Girardon et al. Water solvent has been implicitly considered using polarizable continuum method (PCM). In the case of the first singlet excited state TD-DFT has been used. All the calculations have been performed using the Gaussian09 suite of codes, harmonic vibrational frequencies have been obtained to assure the minimum nature of the stationary point. For benchmark purposes, the absorption spectrum has been calculated as vertical transitions from the GS using different functional namely, CAM-B3LYP, The same levels of theory have also been used to assess the energetic order of the excited states, of both singlet and triplet multiplicity, at S1 and T1 geometries. The excited states have been calculated at TD-DFT level with the Tamm-Dancoff Approximation (TDA), which allows to avoid problems due ot triplet instability and hence provides a more balmanced description of the two multifold. As discussed in the Result section it appears that the combination of 6-31G and wb97XD provides a reliable description of the PES, especially avoiding a computational burden, which will make render the subsequent SH dynamic sampling untreatable. The nature of the excited states has been identified in terms of Natural Transition Orbitals (NTO) obtained via a postprocessing of the Gaussian output with the Nancy_Ex code. To better quantify the nature of the excited states we also calculated the topological fS index which provides the spatial overlap between hole and density matrices. To preliminary assess the possibility of H-transfer and ISC crossing we also performed a relaxed scan at the 6-31G/wb97XD level along the O-H distance d (see Scheme 1 and Figure ) and we also explored the global degrees of freedom potentially leading to ISC by performing a linear interpolation of the internal coordinates to bridge T1 and S1 equilibrium geometries, using the same level of theory as for the relaxed scan. These calculations have been performed with Gaussian 09 code as well. Finally, to assess the competition between the different relaxation routes and their timescales we performed in vacuo SH dynamics using the Sharc code coupled with Orca. This strategy has already been used successfully by some of us on similar biological systems or photosensitizers. To this aim, 200 initial conditions around the Franck-Condon regions have been generated via a Wigner distribution, and the trajectories have been propagated at TD-DFT level, using the 6-31G/wb97XD level of theory, coherently with the previous benchmark. Due to their possible influence in the forthcoming dynamics we have calculated, in addition to the GS, 4 singlet excited states and 4 triplet states. SOC elements have been directly computed at each step of the dynamics with Orca, while the non-adiabatic coupling is approximated via the wavefunction overlap strategy. Considering the high difference in the oscillator strength, more than two order of magnitude, only the S1 state was initially populated. Each SH trajectory has been propagated with a time step of 0.5 fs to assure energy conservation for a total of 2 ps. The analysis of the population and distances have been performed on the ensemble of the trajectories, and the characteristic times have been obtained fitting the resulting evolution of the population to the established kinetic model. The individual trajectories have been analysed and visualized also using the VMD code.