<p>Liquid–liquid phase separation (LLPS)-derived coacervates have recently attracted significant interest as multifunctional carriers, especially in sustainable agriculture applications. However, the intrinsic instability of these membraneless droplets hinders their evolution into advanced functional materials. Herein, inspired by the silica frustule architecture of diatoms, a bioinspired organic–inorganic composite coacervate system is reported. In this design, an in situ-formed silica network envelops each coacervate core, creating a robust core–shell microstructure analogous to a protective exoskeleton. Multi-modal characterization, including imaging flow cytometry, dynamic light scattering, and turbidity titration, demonstrates that the silica shells dramatically enhance droplet stability by preventing coalescence and withstanding environmental perturbations. Importantly, these silica-shell coacervates serve as efficient pesticide carriers, synergistically combining the high payload capacity and biocompatibility of conventional coacervates with markedly improved storage stability and longer-lasting insecticidal activity. This work establishes a new paradigm of compartmentalized coacervate droplets, offering a versatile bioinspired platform for developing application-oriented functional materials that integrate synthetic materials chemistry with biomimetic innovation.</p> Graphical Abstract <p></p>