The crystal structure and the physical properties of the radical ion salts BMT-TTFI2. FeX4 (X = Br, Cl) and (DMET)(2)FeBr4 are investigated. The structures of BMT-TTFI2. FeX4 are characterized as the sheets made of dimerized donor molecules and one-dimensional anion chains. These salts show three-dimensional Curie-Weiss behavior accompanied with antiferromagnetic transitions, with the highest Neel temperature (T-N = 15 K) among the pi -d interaction based magnets for the FeBr4 salt. Within a crystal of (DMET)(2)FeBr4, the donor molecules form one-dimensional columns, between which magnetic anion sheets are inserted. This salt is metallic down to T-MI = 200 K, above which the Curie-Weiss type magnetism is described in terms of donor and anion spins, in spite of the metallic conduction of the salt. Below T-MI the magnetism is governed by anion spins, and an antiferromagnetic phase transition takes place at T-N = 3.5 K.