Aromaticity information is also significant in two of the 13 scaffold tree prioritisation rules for parent scaffold determination, namely rule 7 "A Fully Aromatic Ring System Must Not Be Dissected in a Way That the Resulting System Is Not Aromatic Any More") and rule 11 "For Mixed Aromatic/Nonaromatic Ring Systems, Retain Nonaromatic Rings with Priority") . The seventh rule makes it necessary to generate all possible parent scaffolds producible by the removal of one ring at the given dissection step and apply aromaticity determination to each of them to assess whether aromaticity was lost in the remaining ring(s). Because this consumes a lot of computation time and aromaticity should be conserved in most cases through the double-bond insertion, the application of the seventh prioritisation rule can be turned off individually in Scaffold Generator.