This project addresses the urgent need for efficient removal of antibiotics and textile dyes from water, pollutants that resist conventional treatment and contribute to antimicrobial resistance. Surface modified (multimetallic) zeolitic imidazolate frameworks (ZIFs) are promising candidates for photocatalytic removal of various organic waste, yet major knowledge gaps persist: trimetallic systems remain unexplored, ligand engineering is underutilized, bulk and surface modifications have never been combined and atomic-level structural validation is lacking. The project will develop two libraries of materials: monometallic ZIFs based on four imidazolate linkers, and trimetallic Zn–Co–M (M = Cu, Mn, Fe) ZIFs with engineered metal nodes. Both will be functionalized with conjugated organic molecules to tune light absorption and charge separation. Using an integrated methodology, SCXRD and especially 3D electron diffraction will provide single-crystal data from nanocrystals as small as 50 nm, enabling precise structure solution of novel compositions, while PXRD, BET, ICP-OES, DRS UV-Vis, and EIS will be used for phase purity, porosity, composition, band gap, and charge transfer characterization. Photocatalytic performance toward antibiotics and dyes under visible light will be systematically evaluated, including recycling stability and radical trapping studies. All structural, electronic, and functional descriptors will be merged into a hierarchical structure–property map, from which quantitative design rules will be extracted. An optimal ZIF composition not originally synthesized will be predicted and experimentally validated. The project will generate the first atomic-resolution structures of trimetallic, surface-modified ZIFs, establish rational design principles for next-generation photocatalysts, and contribute to mitigating water pollution and antimicrobial resistance while strengthening international collaboration and training a young researcher.