The fifth option of Scaffold Generator concerns post-processing after ring removal: As explained above, a double bond is inserted in some cases when an aromatic ring is removed to preserve hybridisation and aromaticity in the remaining ring(s) if possible. As an option, this insertion of double bonds can also be applied to non-aromatic systems wherever there are two sp 2 hybridised atoms adjacent to a single bond that was previously shared between two rings. The bond is turned into a double bond if the two adjacent atoms would lose their sp 2 hybridisation because of the ring removal and if it is possible without violating valence rules (Figure ).