In contrast to polydentate ligands, ambidentate ligands can attach to the central atom in either one of two (or more) places, but not both. An example is thiocyanate, SCN^-, which can attach at either the sulfur atom or the nitrogen atom. Such compounds give rise to linkage isomerism.

Polydentate and ambidentate are therefore two different types of polyfunctional ligands (ligands with more than one functional group)