Previous work on the computational modeling of T 1/2 in [Mn(Cp R ) 2 ] (R = Me, i Pr or t Bu) showed that DFT methods (OPBE in particular) were able to correctly model the SCO behaviour in such systems. However, we decide to pursue a systematic benchmark of different DFT methods aiming to be as quantitative as possible towards the calculation of the transition temperature. With that goal, we choose as a benchmark model the [Mn(Cp 1-Me ) 2 ] system for its simplicity, which allows the testing of multiple functionals and basis set schemes, and also because there is structural information in gas phase (d(Mn-C) = 2.433 Å and 2.144 Å for high-and low-spin respectively), as well as a proper characterization of its T 1/2 (303 K), data that will allow us to properly calibrate the computational method of choice.