The theme of supramolecular synthons runs through all disciplines of crystal engineering. The concept of supramolecular synthons has received ever increasing attention in various fields since it was defined and introduced in 1997. This trend is manifest in the exploding number of articles published, and not only in the specialised journals, Crystal Growth and Design and CrystEngComm. Attention is being given both to supramolecular synthons, which involve strong intermolecular interactions, and to weak intermolecular interactions, for instance C–X⋯CN, C–H⋯N, C–H⋯F or X⋯X, in the interpretation and understanding of molecular aggregation in the solid state. This highlight article will give a picture of the rapid development of interest in supramolecular synthons in the last ten years together with a discussion about the boundaries of this concept.