This contribution reports an unprecedentedly efficient dimerization and the first successful polymerization of lignocellulose‐based β‐angelica lactone (β‐AL) by utilizing a selective Lewis pair (LP) catalytic system, thereby establishing a versatile bio‐refinery platform wherein two products, including a dimer for high‐quality gasoline‐like biofuel (C8–C9 branched alkanes, yield=87 %) and a heat‐ and solvent‐resistant acrylic bioplastic (Mn up to 26.0 kg mol−1), can be synthesized from one feedstock by one catalytic system. The underlying reason for exquisite selectivity of the LP catalytic system toward dimerization and polymerization was explored mechanistically. Angel′s advocate: An unprecedentedly efficient dimerization and the first successful polymerization of lignocellulose‐based β‐angelica lactone have been achieved by a selective Lewis pair catalytic system. A versatile bio‐refinery platform is established, whereby two products, including a dimer for high‐quality gasoline‐like biofuel and a heat‐ and solvent‐resistant acrylic bioplastic, can be synthesized from one feedstock by one catalytic system.