**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** CURRENT BIOREFINERY OPERATIONS FACE THE CHALLENGES OF IMPROVING COST COMPETITIVENESS AND CO-PRODUCING VALUABLE BIOPRODUCTS TO MEET MARKET DEMAND. FROM THE PERSPECTIVE OF VIABLE CELLULOSIC BIOREFINERY, A NEW PRETREATMENT METHOD SHOULD BE ABLE TO GENERATE HIGH-QUALITY TECHNICAL LIGNIN FOR FURTHER UPGRADING WHILE ENSURING EFFICIENT HOLOCELLULOSE CONVERSION. TO THIS END, WE PROPOSE A NOVEL INTEGRATED APPROACH ENABLED BY DEEP EUTECTIC SOLVENTS (DESS) TO CONVERT LIGNOCELLULOSIC BIOMASS TO PLATFORM CHEMICALS (I.E., FURFURAL, 2,3-BUTANEDIOL (2,3-BDO)) AND CARBON FIBERS. GREEN, LOW-COST, HIGHLY TUNABLE SOLVENT SYSTEMS WILL BE DEVELOPED FOR SIMULTANEOUS BIOMASS FRACTIONATION AND FURFURAL PRODUCTION, ENSURING ATOM-EFFICIENT XYLAN CONVERSION WHILE SUPPLYING READILY DIGESTIBLE PULP FOR 2,3-BDO PRODUCTION. THE RESULTING TECHNICAL LIGNIN IS EXPECTED TO YIELD MECHANICALLY STRONG AND HIGHLY ELECTRICALLY CONDUCTIVE CARBON FIBERS. THE SUCCESSFUL COMPLETION OF THIS PROPOSED RESEARCH WILL PROVIDE NEW INSIGHTS INTO BIOMASS DECONSTRUCTION, HOLOCELLULOSE CONVERSION, AS WELL AS LIGNIN TRANSFORMATION INTO ADVANCED CARBON. IT WOULD LEAD TO COST-EFFECTIVE PRODUCTION OF RENEWABLE CHEMICALS AND CARBON FIBERS FROM LIGNOCELLULOSIC BIOMASS. IT WOULD ALSO PROVIDE A VERSATILE PLATFORM TO ENABLE PRODUCT-DRIVEN BIOREFINERY WITH REDUCED CARBON FOOTPRINT AND IMPROVED ECONOMIC PROFITABILITY.