When approaching the synthesis of a material that requires rigorous control over multiple features (e.g. composition, crystal structure, shape, size), it is helpful to understand how the material forms, including how each variable influences its formation. Realistically, though, this is not always possible, particularly for inorganic solids that form at high temperatures and colloidal nanoparticles that form in solution. We have been studying the reaction pathways that lead to the formation of inorganic solids and nanostructures with the goal of developing retrosynthetic capabilities for target-oriented materials synthesis. This talk will emphasize recent efforts in elucidating the reaction pathways that produce complex hybrid nanoparticles, including new insights into chemoselective growth and the development of reactive solid-state synthons that lead to new classes of multi-functional nanostructures. This talk will also include the design and synthesis of new bulk and nanostructured solid-state materials with useful catalytic properties and crystal structures that are not routinely accessible using traditional methods.