Chitosan was modified through the hydrogel synthesis route and its catalytic activity was evaluated for the synthesis of jasminaldehyde by the condensation of 1-heptanal with benzaldehyde under solvent-free conditions. Chitosan being natural product and also the solvent-free synthesis procedure of jasminaldehyde have the advantage of green catalysis. Maximum conversion of >99% and 88% selectivity to jasminaldehyde were obtained at 160 degrees C. The effect of reaction parameters such as the amount of the catalyst, temperature and the benzaldehyde to 1-heptanal molar ratio on the conversion and selectivity was studied. The catalyst was recycled up to six times without significant loss in its activity and selectivity. (C) 2010 Elsevier B.V. All rights reserved.