We synthesised CrCl 2 (pym) by reacting CrCl 2 with pyrimidine. We found that the monopyrimidine CrCl 2 (pym) forms in a wide variety of solvents and stoichiometries, and even via neat combination and with excess ligand, although bispyrimidine analogues are known for other transition metals. Single crystals suitable for X-ray diffraction measurements were grown through vapour diffusion. We solved the structure from single-crystal X-ray diffraction (SCXRD) data and found that CrCl 2 (pym) crystallises in the monoclinic space group P 2 1 /m with two formula units in the unit cell (Tab. S1). The Cr 2+ are coordinated by four Cl -ligands and two N atoms from the pyrimidine ligands, which forms a distorted CrCl 4 N 2 octahedron (Fig. &). The chromium octahedra edge-share through the Cl - ligands along the crystallographic a direction, and these chains are connected by pyrimidine ligands along the crystallographic b direction with an alternating orientation to form corrugated layers (Fig. ). These layers stack in the crystallographic c direction through van der Waals interactions (Fig. ). oxidation state after exposure to air (Fig. ). As we expected CrCl 2 (pym) to be an S = 2 2D magnet, we measured its temperature dependent magnetic susceptibility, χ(T ). The 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. These data show a broad peak at 20-25 K characteristic of short-range ordering and low-dimensional magnetism (Fig. ). The dχ dT (T ) data show a discontinuity at 20 K, indicating a phase transition from a disordered magnetic state to a long-range ordered AFM state (Fig. ).