The presence of a three-dimensional hydrophilic network structure ensures the uniqueness and wide practical application of hydrogels in industry, medicine, agriculture, etc. On their basis, soft contact lenses, dressings, superabsorbents, catalysts, soil structuring agents, preventing root drying and improving plant survival, have been created. The aimof this work is to synthesize new water-swellable polymer composites by combining monomer units of various natures based on acrylic acid and agar-agar with imidazole, differing in hydrophilic-hydrophobic balance. Results and discussion: The synthesis of new double and ternary polymer composites based on acrylic acid and agar-agar with imidazole was carried out, their physicochemical and complex-forming properties with transition metal ions in an aqueous medium were investigated. Comparative analysis showed that the complexation of interpenetrating networks with FeCl3 is more pronounced than with CoCl2. This fact can be associated with the difficulty of introducing a cobalt ion into the ligand plane during the formation of a metal complex, which further affects the binding to the functional groups of the network. The specific binding of the obtained polymer composites with metal salts was shown, which is carried out through the formation of ion pairs with the participation of counterions and coordination-unsaturated metals, which make the main contribution to the formation of extracomplexes and are responsible for the coordination of oxygen-containing ligands.