Hydrogen bond-mediated self-assembly is a powerful strategy for generating large structures from smaller subunits. The synthesis of molecules containing two isophthalic acid units covalently attached to a rigid aromatic spacer is described. By normal pairing of carboxylic acids into hydrogen-bonded dimers, these molecules self-assemble in organic solvents to form either a series of linear aggregates or a cyclic hexamer. These molecules were linked to the core of a family of polyether dendrimers, which caused the hexamer to be formed preferentially. The stability of the hexamer depended on the generation number of the dendrimer. The largest of these hydrogen-bonded macromolecular assemblies is roughly disk-shaped with a 9-nanometer diameter and a 2-nanometer thickness. Its size and molecular mass (34,000 daltons) are comparable to that of small proteins.

The concept of orthogonality has been applied to many areas of chemistry, ranging from wave functions to chromatography. But it was Barany and Merrifield's orthogonal protecting group strategy that paved the way for solid phase peptide syntheses, other important classes of biomaterials such as oligosaccharides and oligonucleotides, and ultimately to a term in widespread usage that is focused on chemical reactivity and binding selectivity. The orthogonal protection strategy has been extended to the development of orthogonal activation, and recently the click reaction, for streamlining organic synthesis. The click reaction and its variants are considered orthogonal as the components react together in high yield and in the presence of many other functional groups. Likewise, supramolecular building blocks can also be orthogonal, thereby enabling programmed self-assembly, a superb strategy to create complex architectures. Overall, orthogonal reactions and supramolecular interactions have dramatically improved the syntheses, the preparation of functional materials, and the self-assembly of nanoscale structures.