Having synthesised and determined the structure of these four vdW MOMs, we sought to understand their bulk magnetic properties. The variable-temperature susceptibility, χ(T ), for each sample was measured under field cooled (FC) and zero-field cooled (ZFC) conditions in a 0.01 T dc field from 2 K to 300 K, and the isothermal magnetisation, M (H), was measured at a range of temperatures between -5 T and 5 T for M = Fe and -14 T and 14 T for M = Ni. The χ(T ) data for FeCl 2 (pym), FeCl 2 (btd) and NiCl 2 (pym) show a sharp cusps at 10.5(5) K, 3.8(2) K and 15.8(7) K respectively, which are characteristic of a transition to a long-range ordered antiferromagnetic state (Fig. ). In contrast, NiCl 2 (btd) shows a bifuraction between the ZFC and FC χ(T ) data at T = 17.5(5) K, indicative of ferromagnetic ordering (Fig. ). The dχ dT (T ) data show discontinuities at these temperatures, providing further evidence of magnetic order (Fig. , S8d, S10d, S12d).