Treating an organic crystal as a supermolecule, crystal engineering may be considered as a solid-state supramolecular equivalent of organic synthesis. By analogy with synthons in organic synthesis, Desiraju[11] introduced the term supramolecular synthon as structural units within supermol ecules which can be formed and/or assembled by known or conceivable synthetic operations involving intermolecular interactions Supramolecular synthons(Scheme 3.1) are spatial arrangements of intermolecular interactions between complementary functional groups. The synthons well describe the recognition events that take place when molecules assemble into crystals. With the convenience of simplifying a crystal structure as a network l 12l. the analysis of a complex target