This feature article introduces new structural motifs (referred as "samogen") that serve as the building blocks of hydrogelators for molecular self-assembly in water to result in a series of supramolecular hydrogels. Using a compound that consists of two phenylalanine residues and a naphthyl group (also abbreviated as NapFF (1) in this text) as an example of the samogens, we demonstrated the ability of the samogens to convert bioactive molecules into molecular hydrogelators that self-assemble in water to result in nanofibers. By briefly summarizing the properties and applications (e.g., wound healing, drug delivery, controlling cell fate, typing bacteria, and catalysis) of these molecular hydrogelators derived from the samogens, we intend to illustrate the basic requirements and promises of the small-molecule hydrogelators for applications in chemistry, materials science, and biomedicine.