In the present scenario most of the synthetic polymers, because of their biocompatibility and biodegradability are much more limited than those of the natural polymers such as Cellulose, Chitin, Chitosan and their derivatives. Chitin and Chitosan are more versatile, renewable and promising biomaterials waiting for commercial promotion. The reaction of chitosan is considerably more versatile than cellulose because of the presence of NH2groups. Application of Chitosan in the field of medicine, agriculture, food, cosmetics, and biopharmaceuticals is a remarkable one. This manuscript presents the preparation of chitosan membranes cross linked with sulphuric acid to improve the proton conductivity. This also throws light on the characterization of the membranes by UV-Vis, FTIR- XRD. The interaction detected decreases the membrane crystallinity which can be used to monitor the progress of the cross linking reaction. The optical absorption and transmittance data are used for the identification of band gap, refractive index, extinction co-efficient and nature of the transitions