A review; chem. industries leave much room for improvement in the areas of environmental conservation and resource utilization efficiency. The development of superior catalytic technologies is one priority area when considering current problems faced by society and the global environment. We have designed a variety of highly functionalized polyoxometalate (POM) catalysts for application to achieve environmentally-friendly chem. processes. The following four topics are described in this account: (i) high functionalization of tungstates, (ii) construction of multimetallic active sites effective for concerto catalysis, (iii) base catalysis with POMs, and (iv) the development of POM-based heterogeneous catalysts. [on SciFinder(R)]