<p>Heterophase assembly of metal-organic framework (MOF) units on solid supports offers a versatile route to composite catalysts, but precise manipulation over the control of interfacial coordination environment to tailor active sites remains challenging. Herein, we report a controllable Layer-by-Layer (LbL) assembly strategy for the in-situ fabrication of ZIF-67-like unit/Silica composites, enabling systematic investigation of diverse support structures govern the interfacial coordination states, including worm-like mesoporous BMMs, straight channels MCM-41, and SiO₂ spheres. Comprehensive characterizations (XRD, N₂ adsorption-desorption, SEM, FT-IR, UV-Raman, TG) were employed to investigate the structure and morphology of the supports, as well as the assembly of metal with ligand. The coordination environments of Co²⁺ were probed through CO₂ cycloaddition with epoxides, XPS, X-ray absorption spectroscopy (XAS), and molecular dynamics simulations. Strikingly, tunable spatial confinement effects from different supports dictate the Co²⁺ coordination saturation: open SiO₂ surfaces afforded unrestricted metal-ligand coordination resembling bulk ZIF-67, straight MCM-41 channels imposed severe spatial constraints yielding the most coordinatively unsaturated Co²⁺ centers, while worm-like BMMs provided intermediate confinement enabling tunable coordination saturation. Consequently, BMMs-based composites exhibited superior catalytic activity. Significantly, this study establishes a clear correlation structure-coordination-performance for rational support selection in designing MOF-containing composite catalysts with tailor-made active sites.</p> Graphical Abstract <p></p>