Since long scientists explored natural/bio-polymers to explicit their innate features to develop certain novel utilities in modernization of prevalent Science & Technology. Consequently biotope derived polysaccharide embrace huge prospective desired functions. Amid, chitosan, the second most ubiquitous polymer after cellulose exists as a β-(1-4)-linked d-glucosamine/N-acetyl-d-glucosamine randomly distributed linear polycationic yield from partial deacetylation of chitin polysaccharide. Chitin's complexity limits its extraction/insolubility in aqueous solution, thus less studied/research until 1980s. As major polysaccharides are either neutral/negatively charged in an acidic environment, instead chitosan is cationic, eventually forms electrostatic complexes/multilayer structures/composites with anionic synthetic dopants/natural polymers. Chitosan own biocompatibility, non-toxicity, low allergy and biodegradability allow utility as in water treatment, wound-healing, pharmaceutical excipient/drug carrier, obesity treatment and scaffold for tissue engineering. It is reflected in the increasing number of related publications throughout in biomedical, environmental and industrials applications. Feeble chitosan solubility limits their applications, yet benign synthetic techniques viz.; sol-gel, encapsulation, chemical grafting are employed to yield composites/ hydrogels/films/granules which generates new functionality, besides enhanced biocompatibility and biodegradability. This chapter presents the R&D, trends and the latest prospects involved in advance synthesis of chitosan supported composites/ hydrogels/films/granules/sheets with special highlighted pharmaceutical/biomedical and environmental applications.