A new homometallic trinuclear Ni(II) complex [(NiL)(2)Ni(NCS)(2)] (1) and three heterometallic trinuclear Ni(II)-Zn(II)-Ni(II) complexes [(NiL)(2)Zn(NCS)(2)] (2), [(NiL)(2)Zn(NCS)(2)(CH3OH)(2)]center dot 2CH(3)OH (3) and {[(NiL)(2)Zn(NCS)(2)(CH3OH)(2)]} {[(NiL)(2)Zn(NCS)(2)]} (4) have been synthesized by using the "complex as ligand" approach with the "metalloligand" [NiL] (H2L = N,N'-bis(salicylidene)-1,3-propanediamine) and thiocyanate in different ratios. All the complexes have been structurally and magnetically characterized. In the isomorphous complexes 1 and 2, the two terminal square planar Ni atoms and the central octahedral nickel Ni atom (in 1) or zinc atom (in 2) are arranged in a bent structure where two cis kappa N-SCN- thiocyanate ions are coordinated to the central atom. The chemical composition of 3 is very similar to that of 2 but, in 3, the central Zn atom is tetrahedral and the kappa N-SCN- thiocyanate ions occupy an axial position of each terminal nickel atom (which now are octahedral with the sixth position occupied by a methanol molecule). Complex 4 consists of two closely related trinuclear units 4A and 4B. In 4A, the coordination environments of the metals are identical to those of 3 whereas 4B is a "coordination position isomer" of complex 2 with the central square pyramidal Zn and one of the terminal square pyramidal Ni atoms coordinated by two kappa N-SCN- thiocyanate ions. Complex 4 is a unique example of a cocrystal formed by two similar trinuclear units (4A and 4B) where 4A is identical to an existing complex (3) and 4B is a "coordination position isomer" of another existing complex (2).