In this communication, we discuss the design, synthesis, and characterization of four peptides which are able to self-assemble into five different homo- and heterodimeric a.-helical coiled coils based on the pH of their environment. These peptides are very short, containing only 14 or 21 amino acids each, and illustrate the minimum requirements necessary to form dimeric coiled coils which are critical in a large number of biological and materials design applications.