The combination of contemporary synthetic chemistry and application-driven materials design accentuates the opportunities available at the intersection of science and engineering to advance soft, flexible, and biocompatible devices. Designing devices which will undergo deformation can be approached in two ways: (1) mitigating deformation to realize strain-tolerant devices that maintain functionality in dynamic environments, e.g., wearable devices that bend and stretch with the body, or (2) leveraging deformation as a device input or output, e.g., strain sensing or actuation. In both cases device performance can be optimized through materials development, guided by electro-mechanical modeling.Devices which leverage deformation have figures of merit that are closely linked to material mechanics. It is of interest to develop novel materials that defy conventional boundaries of mechanical behavior. Bottlebrush elastomers are an emerging class of solid materials that exhibit extremely low elastic moduli. Super-soft bottlebrush elastomer dielectrics and conductive composites have utility in enhancing the performance of flexible devices such as capacitive pressure sensors. Mitigating deformation requires quantitative modeling of strain-dependent device parameters. One particularly interesting device to model is the thin film transistor (TFT), an important building block of modern circuits. Organic TFTs can be made with materials that allow them to be deformed during electrical operation. Mechanical models of the elasticity of polymers can be applied to predict the electrical characteristics of deformable TFTs.