Phase-separated coacervates can enhance reaction kinetics and guide multilevel self-assembly, mimicking early cellular evolution. In this work, we introduce “reactive” complex coacervates that undergo chemically triggered self-immolative transformations, directing the self-assembly of the reaction products within their matrix. These self-assemblies then evolve to show life-like properties such as budding and membrane formation. We find that the coacervate composition critically influences reaction rates and product distribution and guides the hierarchical self-assembly. This work showcases “reactive” coacervates as a versatile platform to influence reaction and self-assembly pathways for controlled supramolecular synthesis and hierarchical self-organization in confined spaces.