Polysaccharides are intricate biopolymers abundantly found in nature and hold astounding potential in fostering sustainability initiatives by providing eco-friendly solutions for waste management, pollutant remediation, and the development of recyclable materials, which aligns with the global agenda for a sustainable future. Notably, advancements in 3-D technology have revolutionized the world of material synthesis, including the polysaccharide fabrication landscape by enabling layer-by-layer architectural designing of materials with improved properties such as tunability, biocompatibility, recyclability, specificity, selectivity, and adsorptivity, which are important in various applications. Thus, this book chapter focuses on 3D-engineered polysaccharide nanocomposites (TDPSNC) for different applications. Firstly, this work presents various 3-D strategies for the synthesis of TDPSNC to set the tone of the study. Thereafter, recent advances in environmental, energy, and medical applications of various TDPSNCs, especially in environmental remediation, were pragmatically discussed with a specific focus on their performance. Furthermore, their recyclability/biodegradability potential was analyzed to provide empirical clues about their industrial applicability, cost-effectiveness, and circular economy value. In the end, challenges, frontiers, and future prospects in the areas of artificial intelligence, machine learning, and neural networks for TDPSM properties manipulation were highlighted to advance the field.