Sustainable conversion of waste biomass and their feedstocks into well-defined nitrogen-containing molecules is of prime interest due to the widespread applications of amines in chemical industries and life science. However, there exists a severe challenge for efficient and selective conversion of waste biomass because of its rigid structure, high moisture content, and low density. The last 10 years have witnessed rapid-growing research interest in the area of biomass utilization to useful products. The present chapter focuses on multiple opportunities offered by catalytic and noncatalytic biomass depolymerization with particular emphasis on various resources of biomass (carbohydrates, chitin, fatty acids/esters, lignin, and natural biomass) to nitrogen-based chemicals. © 2022 Elsevier Inc. All rights reserved.