How do materials form from molecular precursors?Controlling nucleation and growth from atoms and molecules in solution into their final physical states underpins the synthesis of functional materials. Yet, the link between the solution chemistry and the final material remains weak, which limits the rational synthesis design of materials.Here, we propose a molecular chemistry (MC) model which links the choice of precursor chemistry to the shape selectivity in the synthesis of colloidal nanocrystals (NCs), as a case example. We select this class of solution-made materials because of the impact of their size- and shape-dependent functional properties on several technologies. The MC model rationalizes shape selectivity by connecting the molecular precursor chemistry to the bonding characteristics of the forming nuclei, which in turn determine the final NC shape. The proposed MC model establishes a theoretical framework that offers atomic-level insight and chemical consistency in understanding the NC formation. By employing a bond-counting approach to address the complexity of nucleation, the MC model represents the first step toward more broadly applicable design principles for diverse solution-made material systemsFundingThis work was primarily financed by the Swiss National Science Foundation (SNSF) (Grant Number 200021_219715/1)ReferencesZ. Chen, L. Zaza, A. Loiudice, R. Buonsanti "A Molecular Chemistry Model Links Precursor Chemistry to the Energetic Landscape of Shape-Controlled Colloidal Nanocrystals" J. Am. Chem. Soc. 2026, 148, 24008; doi/10.1021/jacs.6c04063