The title complex, [Mg(3)(CHO(2))(3)(C(9)H(3)O(6))(C(3)H(7)NO)(3)](n), exhib-its a two-dimensional structure parallel to (001), which is built up from the Mg(II) atoms and bridging carboxyl-ate ligands (3 symmetry). The Mg(II) atom is six-coordinated by one O atom from a dimethyl-formamide mol-ecule, two O atoms from two μ(6)-benzene-1,3,5-tricarboxyl-ate ligands and three O atoms from three μ(3)-formate ligands in a distorted octa-hedral geometry.