PMID: 11263881 Molecules are structured aggregates of atoms joined by chemical bonds; crystals are aggregates of molecules, interacting covalently or noncovalently. The work described in this Account uses molecules, crystals, and other forms of atomic/molecular matter to suggest principles that can be used in generating structured aggregates of millimeter-scale components, interacting through capillary interactions. The properties of these aggregatesthat is, their chemistrymimic aspects of the chemistry of molecules.