Polyoxovanadates (POVs), known for their wide applicability and relevance in chemical, physical and biological sciences, are a subclass of polyoxometalates and usually self-assemble in aqueous-phase, pH-controlled condensation reactions. Archetypical POVs such as the robust [V^IV ₁₈O₄₂]¹²⁻ polyoxoanion can be structurally, electronically and magnetically altered by heavier group 14 and 15 elements to afford Si-, Ge-, As- or Sb-decorated POV structures (heteroPOVs). These main-group semimetals introduce specific chemically engineered functionalities which cause the generally hydrophilic heteroPOV compounds to exhibit interesting reactivity towards organic molecules, late transition metal and lanthanoid ions. The fully-oxidised (V^V), mixed-valent (V^V/V^IV and V^IV/V^III), “fully-reduced” (V^IV) and “highly-reduced” (V^III) heteroPOVs possess a number of intriguing properties, ranging from catalytic to molecular magnet characteristics. Herein, we review key developments in the synthetic and structural chemistry as well as the reactivity of POVs functionalised with Si-, Ge-, As- or Sb-based heterogroups.

The non-covalent interactions between polyoxometalates and inorganic- and organic-based moieties give rise to functional nanoassemblies with diverse potential in applied science.

A novel N,N′-diphosphanyl-imidazol-2-ylidene acts as a stable, hybrid PC_NHCP ligand for M₂ or linear M₃ (M = Cu, Ag, Au) arrays with metallophilic interactions.

A new strategy has been reported for loading of polyoxometalates into metal–organic frameworks. It grants access to bifunctional electrocatalysts for hydrogen and oxygen evolution reactions.