Sustainability and zero-carbon have attracted the great attention of the growing scientific community. ‎Lignin is well known as a potential feedstock for bio-aromatics, in particular, oxygenated ‎aromatics; however, the lignin degradation/depolymerization processes generate a ‎complex mixture of products. There are various methods to convert lignin into a variety of ‎commercial oxygenated aromatics such as vanillin and p-hydroxybenzoic acid. To conduct the selective degradation/depolymerization, separation, and isolation of the individual compounds or a group of compounds with similar ‎compositions is the challenge that can be investigated using different reagents and extractants, novel extraction or ‎washing method, etc. ‎Therefore, this special issue intends to highlight lignin’s potential in the bio-refinery ‎processes, lignin pretreatment procedures,‎ new or improved lignin extraction methods, ‎chemical and catalytic conversions, and lignin valorization. Also, energy-saving and ‎economic studies on strategies to improve lignin applications in industrial fields are ‎other aspects that need to be paid attention to.