This paper describes the effect of the structural properties of ethanol organosolv lignin (EOL) on the productivity of phenolic monomers by solvolysis. EOL was isolated from yellow poplar as a function of the fractionation combined severity (CSF). Structural properties of EOL such as volatile matter, molecular weight, and nitrobenzene oxidation (NBO) yield were significantly decreased with the increasing severity. The highest EOL yield (12.9 wt.%) was obtained at CSF 2.0, but,it also showed a significant decrement of NBO yield and molecular weight, and as a result, the yield of phenolic monomers after solvolysis was low (23.3 mg/g EOL). Despite of slight low fractionation yield (9.0 wt.%), the maximum yield of phenolic monomers after solvolysis was obtained from EOL fractionated at CSF 0.6 (40.4 mg/g EOL; 3.6 g/kg dry biomass), which has a considerably high NBO yield and aryl-ether linkages than EOL fractioned at higher CSF. (C) 2016 Elsevier Ltd. All rights reserved.