For decades, chemists have strived to mimic the intricate design and diverse functions of naturally occurring systems through the bioinspired synthesis of programmable inorganic nanomaterials. The development of thiol-capped gold nanoparticles (AuNPs) has driven advancement in this area; however, although versatile and readily accessible, hybrid AuNPs are rarely atomically precise, which limits control over their surface topology and therefore the study of complex structure-function relationships. Here, we present a bottom-up approach to the systematic assembly of atomically precise hybrid nanoclusters employing a strategy that mimics the synthetic ease with which thiol-capped AuNPs are normally constructed, while producing well-defined covalent nanoscale assemblies with diverse surface topologies. For the first time, using a structurally characterized cluster-based organometallic building block, we demonstrate the systematic synthesis of nanoclusters with multivalent binding capabilities to complex protein targets.