Novel heterogeneous iota-carrageenan-based palladium catalysts were prepared and used in Suzuki cross coupling, Heck coupling and the transfer hydrogenation of olefins while using various substrates and solvents. In all of these reactions, heterogeneous systems based on xerogels or hydrogels were found to be active, and in certain cases, they yielded higher conversions than those of the homogeneous parent systems. Moreover, all the catalysts could be easily separated from the reaction mixtures and recycled without loss of activity.