A Biomimetic Self‐Reinforcing Recyclable Multifunctional Sustainable Material Harnessing π‐Conjugated Cinnamene Units

Abstract Biomass materials offer a promising sustainable development strategy amid escalating global resource and environmental issues caused by plastics. However, incumbent materials suffer from aging when exposed to environmental factors, and their non‐recyclability exacerbates ecological challenges. Inspired by plant self‐repair mechanisms, a self‐reinforcing, recyclable, multifunctional, sustainable polyester material derived from lignocellulosic biomass through a “one stone for multiple birds” strategy is presented. Unlike conventional materials that progressively age under practical environmental conditions, by mimicking plant cell wall structures, this material incorporates an aromatic π‐conjugated cinnamene unit that undergoes [2+2]‐cycloaddition reactions under UV or hygrothermal conditions, significantly enhancing barrier efficiency (O 2 permeability 0.026 barrer, +115%), mechanical properties (Young's modulus 319.3 MPa, +21%), and UV resistance (99.6%, +2%). Additionally, it demonstrates superior solvent resistance, fluorescent anti‐counterfeiting capabilities, and recyclability, enabling a fully sustainable life cycle. This work provides a viable strategy for developing next‐generation biomass plastics that support sustainable development.