The vast amount of biological mysteries and biomedical challenges faced by humans provide a prominent drive for seamlessly merging electronics with biological living systems (e.g. human bodies) to achieve long-term stable functions. Towards this trend, one of the key requirements for electronics is to possess biomimetic form factors in various aspects for achieving long-term biocompatibility. To enable such paradigm-shifting requirements, polymer-based electronics are uniquely promising for combining advanced electronic functionalities with biomimetic properties. In this talk, I will introduce our new molecular-design, chemical-synthesis, and physical-processing concepts for polymer semiconductors, which enabled the incorporation of multiple biomimetic properties with advanced electronic and photonic functionalities. Furthermore, enabled by these new materials, we have also created new device designs and fabrication processes for building unprecedented functional devices, including stretchable and bioadhesive biosensors, stretchable neuromorphic devices, and stretchable OLEDs, which all simultaneously achieve high performance and new biomimetic properties.