AbstractCombining gold nanoparticles (GNP) with stimuli-responsive polymers is a fascinating field for applications as sensor materials or in biomedical applications. The synthesis of multi-responsive Au@Polymer hybrid systems in an in-situ approach using tailor-made poly(2-(dimethylamino)ethyl methacrylate) (P(DMAEMA)) precursor synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization is introduced. In particular, because of its multi-responsive behavior, P(DMAEMA) is of great interest and was used as the precursor for the synthesis. For the polymerization of the precursor, we introduce an approach, applying the photoiniferter RAFT (photoRAFT) mechanism applicable for tertiary amine-bearing methacrylic monomers like DMAEMA. By varying the chain transfer agents (CTA), the influence of different RAFT Z-groups on the solubility of the Au-hybrids was studied. Aging effects were observed by transmission electron microscopy (TEM) analyses. A comprehensive dynamic light scattering (DLS) study revealed the thermoresponsive behavior of the Au-hybrids in an aqueous solution. The influence of free polymer in solution on the suspension stability was observed. The capability of crosslinking using 1,5-dibromopentane (DBP) and the CO2 sensitivity of the synthesized hybrids expands the area of their potential application.