The last decade has see the development of sulfur‐containing polyoxometalates (POTMs) as a subclass of the polyoxometalate family. The structural and physico‐chemical properties of this emerging class of compounds is dominating by the striking coordination properties of the [Mo2O2S2(OH2)6]2+ oxothio cation, used as a building block. The cyclic topology of this arrangement corresponds to the main feature of the {Mo2O2S2}‐based compounds, able to develop cycle‐based chemistry. The control of the linear oligomerization of the {Mo2O2S2} core is achieved by the presence of the anionic component, which acts as a template. Here, we report on recent examples which illustrate how the use of various template ions such as halide, sulfate, polyphosphate, and polycarboxylate anions allows to tune the nuclearity of the inorganic host from {Mo8} to {Mo18}. A special focus on behavior in solution is given, highlighting the dynamic and fluxional character of these host–guest systems. The Diffusion Ordered Spectroscopy (DOSY) 1H NMR, carried out on a large series of cycle‐based and capsule‐like compounds, demonstrates that such a method can be applied for the speciation of POM anions in solution. Finally, electrocatalytic behavior of the {Mo2O2S2}‐based compounds is presented. Preliminary results show that the electrocatalytic reduction of protons into hydrogen (HER) could constitute one of the most relevant applications for this class of molecular compounds.