Two new vanadium squarates have been synthesized, characterized by infrared and thermal behavior and their structures determined by single crystal X-ray diffraction. Both structures are made of discrete, binuclear vanadium entity but in 1 , [V(OH)(H 2 O) 2 (C 4 O 4 )] 2 ·2H 2 O the vanadium atom is trivalent and the entity is neutral while in 2 , (NH 4 )[(VO) 2 (OH)(C 4 O 4 ) 2 (H 2 O) 3 ]·3H 2 O, the vanadium atom is tetravalent and the entity is negatively charged, balanced by the presence of one ammonium ion. Both molecular anions are bridged by two terminal μ 2 squarate ligands. 1 crystallizes in the triclinic system, space group P -1, with lattice constants a =7.5112(10) A, b =7.5603(8) A, c =8.2185(8) A, α =106.904(8)°, β =94.510(10)°, γ =113.984(9)° while 2 crystallizes in the monoclinic system, space group C 2/ c , with a =14.9340(15) A, b =6.4900(9) A, c =17.9590(19) A and β =97.927(12)°. From the magnetic point of view, V(III) binuclear species show ferromagnetic interactions at low temperatures. However, no anomalies pointing to magnetic ordering are observed down to 2 K.