A 2D map is created for solid‐state materials based on a quantum‐mechanical description of electron sharing and electron transfer. This map intuitively identifies the fundamental nature of ionic, metallic, and covalent bonding in a range of elements and binary compounds; furthermore, it highlights a distinct region for a mechanism recently termed “metavalent” bonding. Then, it is shown how this materials map can be extended in the third dimension by including physical properties of application interest. Finally, it is shown how the map coordinates yield new insight into the nature of the Peierls distortion in phase‐change materials and thermoelectrics. These findings and conceptual approaches provide a novel avenue to tailor material properties. A 2D map, based on quantum‐mechanical indicators for electron sharing and transfer, intuitively classifies the fundamental bonding mechanisms in solid‐state materials. It also confirms metavalent bonding as one of the fundamental mechanisms. Extending this map in the third dimension makes it possible to include properties of application interest, and it can therefore open up a new route for computational materials design.