The synthesis of a novel series of nickel containing crosslinked metallopolymers has been developed. Nickel(II) is complexed by Schiff base units as part of a mesogenic side chain polymer. Several polymers with different lengths of their aliphatic tails were used. The degree of complexation is in all cases very high which allows the nickel ions of neighbored side chains to order in linear chains. This leads to remarkable ferromagnetic exchange interactions between the nickel centers which are not present in related monomeric model compounds. Elemental analyses, IR-spectroscopic investigations in the region 4 000–400 cm–1, and temperature dependent magnetic susceptibility measurements were carried out to elucidate the structures of these new materials. Fitting the magnetic data to a linear chain model gives exchange constants J between 1 and 8 cm–1. AC-susceptibility and magnetization measurements show that 4 of the 8 samples exhibit cooperative magnetic properties with Curie temperatures between 9 and 15 K, coercitivities up to 590 G and remnant magnetization up to 860 emuG/mol.