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Abstract: The natural world has evolved to seamlessly combine soft and stiff matter to accomplish unique mechanical outcomes. A remarkable example of this is skin, in which extreme softness at low deformation is accompanied by great tensile strengths at large deformation, and thus resistance to rupture. These synergistic mechanical responses represent an enduring goal in the fields of biomimetic materials science and polymer chemistry. In particular, “l(fā)ife-like” synthetic bio-interfacial materials (e.g., prosthetics and wearable electronic devices) remain attractive targets for improving the health and well-being of society. To this end, ring-opening metathesis polymerization (ROMP) is employed to fashion elastomers which surpass state-of-the-art commercial materials in their combined softness, strength, and upper service temperature, showcasing unprecedented versatility. Specifically, through de novo design, norbornene-based thermoplastic elastomers (NBTPEs) are synthesized which possess skin-like moduli (E <100 kPa), high tensile strengths (σ_max >6 MPa), and upper service temperatures of ca. 260°C. Amongst other noteworthy properties, the NB-TPEs are shown to be highly elastic, tough, recyclable, shelf-stable, and able to withstand autoclave steam sterilization with minimal changes to mechanical properties. Moreover, optimized methodologies for precision block copolymer synthesis with chelated ROMP catalysts are described. Here, the “ROMP toolbox” is expanded for the future synthesis of new materials. Accessible protocols are systematically examined in detail which make use of bench-stable ROMP initiators in tandem with readily available monomers (i.e., endo-NB derivatives rather than analogous exo counterparts), and benign additives. The merits of the process are showcased, including excellent control over polymer molecular weight and distributions (M_w/M_n <1.1), functional group tolerance, as well as high chain-end fidelity for the preparation of block copolymers via sequential monomer addition. Direct comparisons reveal that living polymerizations with endo monomers display improved chain-end fidelity and robustness vs. their exo counterparts. A suite of techniques are used to elucidate unique thermomechanical differences between the two sets of polymer isomers. Lastly, stereochemistry is leveraged to pattern thermomechanically disparate domains using visible light as a spatiotemporal tool. A crucial aspect of this process discussed in detail is the design and synthesis of a novel organic-soluble pyrylium photocatalyst that enables bulk patterning without additional cosolvents.