A new Mn III /Mn II tetranuclear complex, [Mn 4 (hmp) 6 (CH 3 CN) 2 (H 2 O) 4 ](ClO 4 ) 4 ·2CH 3 CN (1) has been synthesized from the reaction of 2-hydroxymethylpyridine (Hhmp) with Mn(ClO 4 ) 2 ·6H 2 O in the presence of tetraethylammonium hydroxide. Structural characterization of 1 by X-ray diffraction on single crystal shows that Mn ions are arranged in a double-cuboidal fashion where Mn 2+ are hepta-coordinated and Mn 3+ centers hexa-coordinated. Magnetic properties have been studied and reveal that 1 behaves as a Single-Molecule Magnet (SMM) appearing at the highest temperature known in the Mn 4 /hmp family.