5-HydroxyMethylFurfural as a versatile organic compound is considered as a promising biomass-derived product via hydrolysis followed by dehydration of lignocellulosic biomass using solid catalysts. In this study, lignocellulosic materials (corncob) were utilized to synthesize 5-hydroxymethylfurfural via solid acid catalytic conversion. The precursor of the catalyst material was chemically impregnated with ZnCl prior to carbonization. The solid catalyst was prepared with three different acid concentrations 98%, 96% and 94% of sulfuric acid. The prepared catalyst was characterized by acid density elemental analysis, FTIR, XRD and SEM. The maximum result of the total acid density and amount of SO3H group was recorded as 3.5mmol/g and 0.61mmol/g respectively with high sulfur content of (1.87%). The result from FT-IR spectra of BC-SO3H-1 confirms the incorporation of -SO3H groups into the carbon material. BC-SO3H-1 was selected based on the acid density and elemental analysis of the catalyst. The activity of the selected catalyst (BC-SO3H-1) was studied on the transformation of corncob to 5-hydroxymethylfurfural using biphasic solvent (water: ethyl acetate) and NaCl in the reaction medium. The intermediate result in the hydrolysis\dehydration reaction was analyzed using FTIR and the functional groups observed at the region 3,400cm−1 2,850cm−1 2,930cm−1, 1675cm−1, 1520cm−1, 1221cm−1, 1190cm−1, between 1700-1500cm−1 and 1400-900cm−1 confirms the occurrence of 5-HMF in the intermediate reaction result. Further investigation was done on optimization of process conditions and Design-Expert 7.0 fulfactorial with three factorthree level replicates was done for experimental design. A total of 54 experiments were conducted at process conditions of reaction time (1.3, 2.2 and 3.1hrs), reaction temperature (120, 150 and 180 oC) and water to ethyl acetate solvent ratio (1:1, 1:2 and 2:1 v/v). A maximum 5-HMF yield of 41.8% was achieved at reaction time of 3.1hr, temperature of 180 oC and water: ethyl acetate ratio of 1:2v/va.