Conventional gels and elastomers cannot replicate tissue’s strain-adaptive stiffening. Transition from the super-soft to super-firm mechanical response upon deformation requires a hierarchical organization of different structural motifs that trigger a cascade of deformation mechanisms at different stress levels. As such, the project will address three fundamental and increasingly complex challenges. First, theoretical modeling will establish universal correlations between network architecture and mechanical properties such as stiffness and firmness and will form quantitative guidelines for encoding precise mechanical “phenotypes” in designed polymeric systems. Second, introduction of self-assembling moieties into network architectural code will empower polymer assemblies with strain-adaptive stiffening. Third, incorporation of dynamic crosslinks will impart programmable viscoelastic response and extend our platform to strain-rate responsive mechanical phenotypes. Fulfillment of the project goals will yield a molecular code – collectively enabling the programmable and efficient development of next-generation of tissue-like synthetic materials with both strain- and strain rate-adaptive mechanical properties.