This thesis explores the use of aminobromomaleimide and dithiomaleimide functionalities to probe their environment. These fluorescent functionalities were incorporated into responsive polymeric nanostructures allowing their behaviour to be read-out upon external stimuli. \ud \ud Chapter 1 gives a brief introduction on nanoparticles formation and the polymerisation techniques used throughout the thesis. The properties of bromo- and thio-maleimides and their use in protein and polymer chemistry were also introduced. \ud \ud Chapter 2 describes a morphology transition simultaneously with a fluorescence on-to-off switch as a result of the modification of the dithiomaleimide substituent. \ud \ud Chapter 3 presents the synthesis of a library of aminomaleimides and explores their fluorescent properties. \ud \ud In Chapter 4, the fluorescent properties of aminobromomaleimide were incorporated into CO2-responsive polymeric nanoparticles for a built-in read-out of the CO2-response. \ud \ud Chapter 5 explores the possibility of using the fluorescent properties of aminobromomaleimide to read-out the behaviour of glutathione-responsive particles