The reaction energy profile for olefin metathesis with 2-Mn is shown in Figure . Again, the depicted reaction profile starts with the olefin adduct that can be generated by coordinating an olefin to 2-Mn. The formation of the olefin adduct from the separated singlet reactants is favored by ∆G = -20.4 kcal/mol (not displayed), while the olefin adduct is more stable in the triplet than in the singlet state. The energetic barrier for the initial [2+2]-cycloaddition on the singlet surface is 11.2 kcal/mol and leads to the formation of a singlet metallacycle with a trigonal bipyramidal geometry. Similar to the situation of 1-Mn, the metallacyclobutane intermediate is more stable in the triplet state than in singlet state with ∆G ST = -7.3 kcal/mol. This trend is again supported by OPBE calculations yielding a ∆G ST value of -12.9 kcal/mol. The barriers for cyclopropanation were calculated to be 30.4 kcal/mol in the singlet state and 18.9 kcal/mol in the triplet state, re- spectively, and are higher in energy than productive OM. In addition, the total cyclopropanation reaction is an endergonic process for both spin states. Note that cycloadditon and cycloreversion are symmetry related processes in this specific example and therefore starting points and endpoints, as well as corresponding transition states have the same energy (Figure : Cycloreversion for the S = 1 state is omitted as it is also 5.5 kcal/mol). We would like to point out that, despite of the shortcomings of the system, the metathesis process is preferred over cyclopropanation in both, the singlet and triplet state, which is an important necessity for OM. This also constitutes a major difference to iron-based systems such as 2-Fe, where the triplet state inevitably leads to decomposition. As with 1-Mn/1-Fe, also in the case of 2-Mn/2-Fe, the spin-state ordering in the Mn variant is less sensitive to the chosen density functional than in the Fe counterpart.