Material formation in nature is precisely controlled in all aspects from crystal nucleation, growth to assembly to deliver superior functions. Specific biomolecule-material interactions have been hypothesized to play important roles in these processes. Proteins, polymers and small molecules have been extensively explored to replicate the degree of control in material formation in vitro and for nonbiogenic materials. However the organic-inorganic interfacial interaction is still far from being understood which hinders the further advancement of biomimetic material formation. In this talk I will share our efforts on decoding the myth of biomolecular specificity to material surface and their roles in controlling crystal nucleation and growth. The selection of facet specific short peptides and their abilities in guiding predictable morphology control of Pt nanocrystals will be first demonstrated. Then detailed experimental and theoretical studies on binding mechanism will be discussed. Based on mechanistic understanding, we designed small molecules bearing molecular signature for facet specific adsorption to modulate the nucleation/growth of the Pt and Pt alloy nanocrystals to deliver the expected nanostructures and functions. At the end of talk I will share our recent research on improving catalytic functions of nanocrystals through synthetic design. These studies open up opportunities in understanding the molecular details of inorganic-organic interface interaction, which can one day lead to the development of a library of molecular functions for biomimetic materials design and engineering.