Customizable Supraparticles Constructed from Catechol‐Terminated Molecular Building Blocks with Controllable Intermolecular Interactions**

Abstract Colloidal supraparticles integrated with multicomponent primary particles come with emerging or synergetic functionalities. However, achieving the functional customization of supraparticles remains a great challenge because of the limited options of building blocks with tailorability and functional extensibility. Herein, we developed a universal approach to construct customizable supraparticles with desired properties from molecular building blocks obtained by the covalent conjugation of catechol groups with a series of orthogonal functional groups. These catechol‐terminated molecular building blocks can assemble into primary particles driven by various intermolecular interactions (i.e. metal‐organic coordination, host–guest, and hydrophobic interactions), and then further assemble into supraparticles governed by catechol‐mediated interfacial interactions. Our strategy enables the formation of supraparticles with diverse functionalities, such as dual‐pH responsiveness, light‐controllable permeability, and non‐invasive fluorescence labeling of living cells. The ease with which these supraparticles can be fabricated, and the ability to tailor their chemical and physical properties through the choice of metals and orthogonal functional groups used, should enable a variety of applications.