This lecture covers the supramolecular organization of л-conjugated molecules in the solid state, discussing their shapes, crystal structures, and packing arrangements. It explains the different types of crystal structures adopted by é-conjugated hydrocarbons, the packing arguments for observed structures, and the polymorphism of certain molecules. The lecture also delves into the crystal structures of benzene, hexaphenylene, pentacene, benzothienobenzothiophene, pyrene, coronene, bisbenzocoronene, dihexylquaterthiophene, didodecyl benzothienobenzothiophene, rubrene, and hexakis(dodecyl) hexabenzocoronene, highlighting their unique features and packing modes.