The first first target molecule, namely triperyleno [3,3,3] propellane (see Figure .a), is characterized by a rather unusual shape and a rather stiff scaffold, constituted by three anthracene rings placed as wings and connected via three 5-atom rings. Such a peculiar structure makes it difficult to obtain accurate FF parameters from transferable databases. Nonetheless, for comparison purposes, we first assembled a standard GAFF potential through the PrimaDO-RAC software (see section S5.1 in the supporting Information), which allows for the automatic generation of a GAFF topology file in GROMACS format. Successively, a QMD-FF was built by fitting QM data with the JOYCE3.0 protocol at PBE/6-31+G(d,p) level of theory as detailed in Table . Just by looking at target I's structure, it is evident that large amplitude oscillations of the various rings are not possible because of the constrained arrangement of the bonds, whereas only small distortions around the equilibrium geometry should be expected in ambient conditions. For this reason, as reported in Table , besides the stretching and bending potentials defined in equations ( ) and ( ), only stiff harmonic torsions (8) were employed to build the QMD-FF. Harmonic torsion describe more appropriately the small amplitude oscillations distorting the aromatic rings. Conversely, the GAFF automated parameterization employs the standard Fourier series (9) to describe all the dihedrals. The intramolecular QMD-FF parameterized with JOYCE3.0 was validated by comparing selected features to both those obtained with the general purpose FF and at QM level, as summarized in Figure . First, propellane's QM and QMD-FF optimized structures are compared visually in Figure .a, whereas the vibrational