Self-assembly has been utilized for the spontaneous formation of nanoarchitectures. Therein, a small change in the molecular structure dramatically alters the resulting macroscopic self-assembly morphologies and the consequent material properties. This macroscopic expression of the small initial difference via self-assembly can be alternatively regarded as precise translation of molecular structural information. In this contribution, we offer a novel molecular recognition concept utilizing self-assembly phenomena. A small difference in guest structures affords distinctly different self-assembly modes of fluorescent (FL) chemosensors, leading to their sensory responses characteristic to the guest structures. Thus, self-assembly has now been utilized as a FL sensory system for molecular recognition, particularly, of biologically important molecules and polymers. Here, we demonstrate that the integral magnitude of binding mechanism, self-assembly, and FL response realizes (i) selective FL detection of ATP, (ii) FL differentiation of dicarboxylates and keto-acids, and (iii) unexpectedly selective FL sensing of hyaluronic acid among glycosaminoglycans.