Syntheses, structures and magnetic properties of a heterobridged -phenoxido-1,1-NCO dinickel(II) compound [NiII 2(HL)3(-NCO)].2H2O (1) and a heterobridged bis(3-phenoxido)bis(3-alkoxido)tetranickel(II) system, [NiII4(L)2(HL)2(SeCN) 2(H2O)2].C3H7NO.4H 2O (2), containing a cubanetype NiII4O 4 core, derived from the totradontate Schiff base compartmental ligand N-(2-hydroxyolhyl)-3-methoxysalicylaldimine (H2L) were described. Compounds 1 and 2 crystallize in triclinic P1 and monoclinic P2 1/c systems, respectively. Compound 2, in which the Ni 4O4 cubane core is composed of two 3-phenoxido and two 3-alkoxido moieties, represents the sole example of this type. The variable-temperature (2-300 K) magnetic susceptibilities and magnetizations of these two compounds were measured. The interaction between the metal centres in dinuclear compound 1 is weak ferromagnetic, resulting in an ST = 2 ground state at 2 K. The overall interaction observed in 2 is weak ferromagnetic, leading to an unusual ST = 3 ground state. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA.