The molli combine command then takes in both core and substituent library objects and joins the substituents to the user-specified attachment points on the cores (see the Supporting Information, Figure ). Substituent sets are selected based on the number of user-specified attachment points and a selection rule, which can be the same substituents attached at all core attachment points, permutations of the substituents, combinations of the substituents, or combinations with replacement. The result of this command then produces the enumerated combinatorial library as a MoleculeLibrary object (Figure ). We have previously reported the generation of a bis(oxazoline) (BOX) combinatorial library (Figure ) comprising a total of 96,120 members, with 267 options for 4,4'-oxazoline substitution, nine options for 5,5'-oxazoline substitution including stereochemical analogues relative to the 4,4'-positions, and 40 options for substitution at the methylene group bridging the two oxazoline rings. With the streamlined workflow described in Figure , we successfully obviated manual creation of the full expanded .CDXML file shown in Figure .