A strategy for easily constructing a sensor array that mimics a biological sensory mechanism, i.e., a so-called chemical tongue, based on a single material is reported. An array of aqueous solutions of a cationic block-copolymer modified with an environmentally responsive fluorophore can convert information from the pH-dependent polymer-protein interactions into patterns of fluorescence change. This chemical tongue allowed discriminating (i) 16 different proteins and (ii) mixtures containing various compositions of disease-marker proteins.