Over the past decade, deep eutectic solvents (DESs) have been touted as promising reagents in biomass valorization. This study focused on the novel utilization of type II choline chloride (ChCl)-based DESs by integrating group II metal chloride hexahydrate, namely, calcium chloride hexahydrate (CaCl2 center dot 6H(2)O) and magnesium chloride hexahydrate (MgCl2 center dot 6H(2)O) as the hydrogen bond donors for the pretreatment of oil palm fronds (OPF). Under atmospheric conditions, pretreatment with ChCl:CaCl2 center dot 6H(2)O (125 degrees C and 4.5 h) resulted in dual biomass valorization effects with a delignification of 46.51%, followed by xylose recovery and xylan removal at 54.12% and 78.67%, respectively. Such performance of ChCl:CaCl2 center dot 6H(2)O as a pretreatment solvent expedited the enzymatic glucose (59.31%) and total reducing sugar (63.89%) conversion in the OPF at a subsequent stage. Thus, the characterizations of pretreated OPF samples endorsed the application of type II ChCl-based DESs, particularly, ChCl:CaCl2 center dot 6H(2)O as a propitious approach for ligno-hemicellulose removal in pretreatment.