Two new molecular magnets, based on [M(mnt)2](-) [M = Pt (1) or Ni (2)), were prepared and characterized structurally and magnetically. The [M(mnt)2]- anions form the columnar stack in 1 and 2. Both compounds are expected to be ideal quasi-ID magnets. For 1, the Zm value passes a maximum at - 150 K and increase again below 120 K, a spin transition then occurs at similar to 80 K with 4 K hysteresis. For 2, chi(m) the chi(m) value decreases, exponentially upon cooling and drops rapidly below similar to 90 K. At this temperature a spin transition occurs, with no sizable hysteresis detected upon heating. (c) 2005 Elsevier B.V. All rights reserved.