[eng] We report a study of the interaction between methylmethanetriacetic acid (MMTA) and a tripodal amidopyridine receptor 1, where the geometry of the binding is in part governed by a weak C-H/ð interaction in the presence of six strong N(O)-HâââO(N) hydrogen bonds. There are two possible binding geometries for the 1:1 complex 1âMMTA; combining computational and experimental evidence we demonstrate that the endo binding mode is more favorable as the result of a C-H/ð interaction.