Abstract: One of the possibilities to sophisticate compound syntheses is catalysis using supported catalyst which combines the advantages of both homogeneous and heterogeneous catalyst. An application of Ce(III) inorganic salts, first of all CeCl3.7H2O doped by sodium iodide, not until has been described from start of 21st Century. Twenty communications has been present during this time only. Catalysis by Ce(III) salts has been used for an activation of carbonyl compounds and their derivatives in syntheses.   Easily available, cheap and mechanically and thermally stable industrial cation-exchangers may be used as carriers1. These in connection with complex of cerium in oxidation state of 3+ provide an effective, easily separable and recyclable catalytic system. This system has been studied with a view to its possible synthetic applications on model three-component domino syntheses, i.e. Kabachnik-Fields one-pot synthesis of α-aminophosphonates2, and Prins-Ritter one-pot synthesis of 4-amidotetrahydropyran derivatives3, respectively. It has been discovered that cation Ce(III) supported on a weak acid macroporous cation-exchanger has shown in the studied reactions at least the same or better catalytic activity as salt CeCl3.7H2O, eventually doped by NaI.