The book highlights recent prominent results in the domain of the synthesis of new polyoxometalates with a specific attention to polyoxothioanions, and provides some novelties and perspectives in selected domains such as magnetism, luminescence and nanochemistry, and macroions self-assembly in solutions. The case of “one-pot” syntheses often used and reported in POMs synthesis is studied in terms of more complex solution speciation processes related to highly dynamical situation connected to factors such as pH, ionic strength, reaction time, temperature, counterion nature,...