Deprotonation of the thialdiphosphazane [S[double bond, length as m-dash]PH(μ-N(t)Bu)]2 with a range of metal-bases gives the stable dianion [S-P(μ-N(t)Bu)]2(2-), which is valence-isoelectronic with the widely-used [RN-P(μ-NR)]2(2-) ligand. Structural studies show that the new ligand has adaptable hard-soft character with respect to the coordinated metal centre and that its multidentate nature can be exploited to construct large cage architectures.