Polyelectrolytes play an important role in both natural biological systems and human society, and their synthesis, functional exploration, and profound application are thus essential for biomimicry and creating new materials. In this study, we developed an efficient synthetic methodology for in situ generation of azonia-containing polyelectrolytes in a one-pot manner by using readily accessible nonionic reactant in the presence of commercially available cheap ionic species. The resulting polyelectrolytes are emissive in the solid state and can readily form luminescent photopatterns with different colors. The azonia-containing polyelectrolytes possess extraordinary potency of reactive oxygen species (ROS) generation, enabling them to impressively kill methicillin-resistant Staphylococcus aureus (MRSA), a drug resistant superbug, both in vitro and in vivo.