<p>The spatial distribution of solute atoms—within and between phases—is a foundational aspect of microstructure. While alloying and doping have long been used to modify the properties of metals, ceramics, and semiconductors, less emphasis has been placed on controlling solute behavior at the atomic scale. This article highlights solute engineering as a powerful and emerging lever in materials design. Whether solute atoms cluster, segregate to defects, or partition between phases depends on the local chemical potential along a continuous energy landscape. Yet the resulting atomic&#xa0;scale solute topologies—short-range order, segregation, and partitioning—are distinct in form and consequence, offering diverse routes to tailor structure, function, and performance. A hierarchical framework is presented to map these solute-driven phenomena in both single-phase and multiphase systems, advancing the concept of microstructure-by-design toward atomically resolved control of materials properties.</p> Graphical abstract <p></p>