This contribution reports an unprecedentedly efficient dimerization and the first successful polymerization of lignocellulose-based b-angelica lactone (b-AL) by utilizing aselective Lewis pair (LP) catalytic system, therebyestablishing av ersatile bio-refinery platform wherein two products, including adimer for high-quality gasoline-like biofuel (C 8 -C 9 branched alkanes,y ield = 87 %) and ah eat-and solventresistant acrylic bioplastic (M n up to 26.0 kg mol À1 ), can be synthesized from one feedstockb yo ne catalytic system. The underlying reason for exquisite selectivity of the LP catalytic system towardd imerization and polymerization was explored mechanistically.Dwindling fossil resources,s urging energy demand, and growing environmental concerns have presented ap ressing need for application of naturally renewable biomass as an alternative carbon source. [1] In this context, non-food lignocellulose,w idely available at al ow cost, is the most ideal biomass resource in comparison to starch. [2,3] Considering that polymeric materials and transportation fuels currently account for approximately 50 %o ft otal fossil feedstock consumed annually, [4] the development of catalysis that can effectively convert biomass-based platform chemicals into bio-based polymers [5] or precursors for biofuels [6] has been extensively studied (i.e.bio-refinery). However,the selective production of abio-based polymer and aprecursor for biofuel from one feedstock by one versatile and robust catalytic system, which would be highly desirable,h as remained an unmet challenge.Angelica lactones (ALs), [7] including a-, b-, and gisomeric forms (Scheme 1A), have attracted growing attention recently as they are the key downstream chemicals of levulinic acid, which is available in atotal yield of more than 80 %f rom lignocellulose,a nd was classified recently by the US Department of Energy as one of top 10 biomass-derived compounds best suited to replace petroleum-derived chemicals. [5c, 8] Moreover,v arious value-added chemicals [9] and precursors for biofuels [10] can be produced from ALs,t hus establishing ALs as potential platform chemicals.Asanotable