The coordination chemistry of the polydentate ligand 2,4,6-tris(dipyridin-2-ylamino)-1,3,5-triazine (dpyatriz) with Fe II has been explored, leading through variation of the counterion and the solvent system to the preparation of three different dinuclear complexes: 4 ) 4 (2) and [Fe 2 (dpyatriz) 2 Cl 2 ](CF 3 SO 3 ) 2 (3). The X-ray structure of these compounds has revealed that besides the difference in the noncoordinated anion, complex 1 differs from complex 2 only in the nature of the terminal ligands. Bulk magnetisation studies and Mössbauer spectroscopy have shown that such a subtle difference produces a change to the crystal field on the metal atoms, originating an important disparity of the magnetic behaviour. Thus, complex 1 experiences a partial spin crossover centred at approximately 265 K, whereas com-