Our approach starts with the preparation of hydroxymethylated lignin (HL) from previously characterized softwood kraft lignin (SKL), via electrophilic aromatic substitution using formaldehyde as an electrophile (Figure ). Hydroxymethylation of lignin is highly affected and governed by source of lignin (molecular weight and steric hindrance), type of catalysts, temperature, formaldehyde concentration, and pH. To obtain materials with different extent of reaction at the C5 position of the aromatic ring, we hydroxymethylated SKL at 60 °C and 85 °C keeping the concentration of sodium hydroxide and formaldehyde constant.