A Universal Synthesis Strategy for Tunable Metal‐Organic Framework Nanohybrids**

Abstract Metal‐organic frameworks (MOFs) with encapsulated nanoparticles (NPs) enjoy a vastly expanded application potential in catalysis, filtration, and sensing. The selection of particular modified core‐NPs has yielded partial successes in overcoming lattice mismatch. However, restrictions on the choice of NPs not only limit the diversity, but also affect the properties of the hybrid materials. Here, we show a versatile synthesis strategy using a representative set of seven MOF‐shells and six NP‐cores that are fine‐tuned to incorporate from single to hundreds of cores in mono‐, bi‐, tri‐ and quaternary composites. This method does not require the presence of any specific surface structures or functionalities on the pre‐formed cores. Our key point is to regulate the diffusion rate of alkaline vapors that deprotonate organic linkers and trigger the controlled MOF‐growth and encapsulation of NPs. This strategy is expected to pave the way for the exploration of more sophisticated MOF‐nanohybrids.