Lignocellulosic biomass is an abundantly available byproduct obtained after the separation of edible parts from various crops that is a potential source to produce renewable and sustainable biofuels, chemicals, materials, and polymers, without altering the greenhouse gas emissions relative to fossil feedstocks. Valorisation of lignocellulosic biomass focuses on polysaccharides conversion to value-added chemicals and polymers. However, lignin rich of high carbon burned to generate energy and chemicals. For the development of an effective lignocellulosic biomass conversion technology to biofuels and chemicals, biomass composition analysis and their properties need to be characterized prior to biomass reactions, including polysaccharide hydrolysis and lignin depolymerization. In this work, we have determined alpha-, beta- and gamma- cellulose, pentosan, lignin, and silica percentages of wheat straw (WS) and two bagasse (BG I and II) samples. The impact of different types of biomass samples on composition, and lignin recovery by applying two-stage concentrated and dilute sulphuric acid treatment, has been discussed. Subsequent studies extended to the correlation of lignin properties and their susceptibility to depolymerization using homogeneous (1-methyl-3-(3-sulphopropyl)-imidazolium hydrogen sulphate) and heterogeneous (immobilized Brønsted acidic ionic liquid) catalysts to lower molar mass aromatic fractions. Thermal, physical, and chemical properties of WS, BG, and recovered lignin samples were characterized by using UV-visible, ATR, 13 C CP-MAS NMR, CHNS, XRD, and TGA techniques showed substantial differences in lignin structure and properties.