The synthesis of a cavitand featuring thiourea hydrogen bonding sites and its dimerization in the presence of suitable guests are reported. Dimerization creates a capsule host wider than the corresponding urea or imide structures, and longer alkanes can be accommodated. Specifically, n-C(15)H(32) is encapsulated, but this guest appears folded inside as deduced from NMR studies. Apparently, the plasticity of hydrogen bonds between thiourea groups allows a stable encapsulation complex to persist in solution even though the guest is contorted.