Deconstruction-Reconstruction Strategies Toward Sustainable, Circular Lignocellulosic Materials.

Transition from fossil-based plastics to renewable and circular alternatives requires a fundamental shift of how biomass is deconstructed and reconstructed into value-added products. Lignocellulosic biomass (LCB) represents the largest natural carbon resource on the planet and is made up of cellulose, hemicellulose, and lignin, yet it is still primarily used for low-value products. To advance the field, the capability of biomass as a feedstock for advanced materials necessitates viewing deconstruction and reconstruction not as distinct processes but as a unified, codesigned route. This review enhances that viewpoint by employing the "deconstruction-reconstruction" framework to link biomass fractionation with the potential products generated from it. We critically assess mild activation, component fractionation, and partial degradation through their ability to preserve the functional groups and structural motifs that govern downstream performance. Building on this, we map reconstruction pathways from biomass-derived macromonomers into thermoplastics, thermosets, gel systems, vitrimeric elastomers, coatings, and adhesives. By linking these relationships back to deconstruction chemistry, the review identifies feedstock-process-property combinations that enable high-value circular materials. Finally, we identify the barriers that still limit scale-up, namely feedstock variability, lignin heterogeneity, and solvent recovery, and outline data-driven and green-chemistry strategies for the rational design of circular lignocellulose-based materials.