A homologous series of <i>N,N,N</i>′<i>,N</i>′-tetramethylalkyl-<i>N,N</i>′-dioxides is used to probe the level of guest induced fit attainable in the assembly of a dimeric capsule based on tetraurea benzyl calix[4]pyrrole components. A sensible enhancement of the capsule’s volume was observed in response to guest size for <i>n</i> = 2, 3, and 4. In turn, larger guests adopted folded conformations to adapt to the capsule’s dimensions