The title complex, [Mn(C(5)O(5))(C(12)H(8)N(2))(2)], lies across a crystallographic twofold axis which passes through the Mn atom and bisects the croconate ligand. The two 1,10-phenanthroline (phen) ligands are arranged in a propeller manner and the local mol-ecular geometry of the MnN(4)O(2) unit is severely distorted octa-hedral. This may be inter-preted as a structural perturbation of the MnN(4) square by the croconate ligand. In the crystal structure, the dipole moments of the mol-ecules are arranged alternately along the +b and -b directions. All the phen ligands are involved in π stacking inter-actions, alternately along the [110] and [10] directions. The alternate spacings between the neighbouring phen planes in the one-dimensional π stacks are 3.361 (2) and 3.526 (2) Å.