The experiment described clearly generates a self-assembled state (the gel) in the presence of MeI that is lost once MeI is depleted. The formation/destruction of monoester 15 and diester 16 are also clearly coupled to the alkaline hydrolysis of MeI (c.f. Box 1). However, it is not obvious that the self-assembled material is directly affected by the coupled reaction; the same gross behavior would be observed if the gel fibers were in equilibrium with ester monomer unit 16 but ester formation/hydrolysis took place exclusively in solution (Figure ) or if hydrolysis of 16 took place exclusively in the fibers (Figure ).