The sketch-map that we obtain (Fig. ) includes all predicted structures of the 28 molecules. Isomer Group Index 0.12_4-6_4-6 With the parameters that we chose, the map captures the fact that different molecules can generate similar packing motifs; the 2D map features "islands" of structures that are populated by crystal structures from several different isomers (Fig. ). This finding is consistent with the concept of supramolecular synthons, according to which different molecules can adopt similar crystal packing motifs because they contain similar structure-directing functional groups: in this case, the same set of hydrogen bond donors and acceptors.