Discovery of novel materials is impaired by lack of predictability of solid-state synthesis. In addressing this impediment, an approach toward rational planning of syntheses of solid state and materials is presented. Within the underlying “chemical energy landscape” concept, the whole materials world is projected onto an energy landscape, associated with a respective configuration space. Evidently, all chemical compounds possible are present in virtuo in such a landscape. For the identification of targets for syntheses, these energy landscapes are computationally searched for (meta)stable structure candidates. Moving to finite temperatures, phase diagrams have been established, even including metastable phases, without using any preinformation. The approach presented is physically consistent, and its feasibility has been proven. Quite satisfactorily, many of the predicted compounds were verified experimentally. Synthesis of elusive Na3N, furthermore realizing almost all of its forecasted polymorphs, is a particularly convincing result. Comparisons with competing strategies toward effective materials discovery are drawn.