This report reviews the state of the art concerning the photocatalytic degradation of azo dyes using polyoxometalate-based materials. Recent developments toward polyoxometalates (POMs) and their assemblies that match multiple criteria are described. These criteria include their switchability by visible light, the possibility of multi-electronic photo-reduction of the POMs, followed by reversible electron exchange with a substrate, the possibility of heterogenization without loss of properties and finally a low cost. This strategy is recent and is shown to open up new avenues close to green chemistry achievements for studying the degradation of organic pollutants, including azo dyes.