Coordinatively unsaturated P-substituted dithiophosphonato, dithiophosphato, and dithiophosphito complexes {[Ni((MeO)₂PS₂)₂] (1), [Ni((EtO)₂PS₂)₂] (2), [Ni(MeOdtp)₂] (3), and [Ni((Ph)₂PS₂)₂] (4)} were reacted with the bis-functional ligands 3,5-di-(4-pyridyl)-1,2,4-thiadiazole (L1) and 3,5-di-(3-pyridyl)-1,2,4-thiadiazole (L2) to give the coordination polymers (1–4·L1)_∞, (3·L2)_∞, and (4·L2·2C₇H₈)_∞ and the discrete dimers (1–2·L2)₂, all characterised by single crystal X-ray diffraction. A comparison of the structures shows that L1 can be exploited for the predictable assembly of undulating chains independent of the nature of the Ni^II complex, while L2 allows for the existence of different supramolecular constructs ensuing from different ligand conformations deriving from the rotation of the pyridyl rings.