Amphiphilic triblock terpolymers have attractive applications in the preparation of nanoparticles with controlled morphology. An additional level of morphology control can be provided by reactive blocks, whose interactions with the solvent vary under different stimuli. In this work, we synthesized a triblock terpolymer (poly(acrylic acid)-b-poly(4-hydroxystyrene)-b-poly{1-[4-(1-methyl-1,2-dicarba-closo-dodecaborane-2-yl methyl)-phenyl]ethylene}) (PAA-b-PHS-b-PSC) containing carboranes as pendant groups by reversible addition fragmentation chain transfer (RAFT) polymerization and subsequently studied its behavior in aqueous solution. Once the nanoparticles were formed, the solubility of the second and third blocks was changed via pH and CsF reactions, respectively. The resulting micelles work as an ON/OFF system, using changes in fluorescence intensity at different pH values.