The combination of controlled living polymerization in association with rapid and highly efficient macromolecule conjugation strategies provides a powerful tool for the synthesis of novel polymeric materials. Here functional block copolymers were rapidly and quantitatively conjugated using an efficient reaction between polymers containing a phenolic group and the 4-phenyl-3H-1,2,4-triazole-3,5(4H)-dione (PTAD) moiety, and used to generate nanoparticles that encapsulated drugs. Although generic polymeric nanoparticles have limited potential for cancer targeted drug delivery, improved targeting efficiency and controlled release can be mediated by pH. Here pH responsive amphiphilic block copolymers, which self-assemble into nanoparticles, were fabricated using our novel polymer conjugation strategy with the resulting system designed to promote drug release within the acidic milieu of the cancer microenvironment. The conjugation strategy also enabled the direct tagging of the nanoparticles with a range of fluorophores and/or targeting assets, with cargo release demonstrated in cancer cells.