Five binuclear complexes with rectangular topology have been synthesized using a nitronyl-nitroxide ligand (L) functionalized with a pyrazole coordinating group: [Ln₂(hfac)₂L₂], with Ln=Eu (1), Gd (2 a, 2 b), Tb (3), Dy (4), Tm (5). The Eu^III and Tm^III complexes crystallize in the P2₁/n space group, while the Gd^III, Tb^III, and Dy^III derivatives crystalize in P-1 space group. The crystal structures for compounds 2 a, 3, 4, and 5 have been fully solved, while for compounds 1 and 2 b, the unit cell parameters have been measured and compared with crystals 3 and 5. Crystals 2 a (P2₁/n) and 2 b (P-1) are polymorphic forms. In these complexes the nitronyl-nitroxide ligand bridges two metal ions through one aminoxyl group and the pyrazole fragment. In the five complexes the Ln^III ions show a coordination number of eight with a triangular dodecahedron geometry. The magnetic properties of all five complexes have been investigated. For compounds 2, 3, and 4 the Ln^III-Rad interaction was found to be ferromagnetic: J_GdRad=2.09(1) cm⁻¹ [H=-2J_GdRad(S_Gd1S_Rad1+S_Gd2S_Rad2], J_TbRad=1.93(14) cm⁻¹, J_DyRad=1.72(14) cm⁻¹. The Tm^III-Rad coupling is antiferromagnetic (J_TmRad=−0.53(1) cm⁻¹). For the Tb^III, Dy^III, and Tm^III complexes the effects of the crystal field have been taken into account in the fitting procedure.