A method of using a composite or a composite structure as a catalyst, or catalyst precursor, for a coupling reaction, wherein the composite comprises catalytic metal nanoparticles dispersed in a continuous phase comprised of a polymer having a phenylene group unit and an alkylene group unit, the alkylene group having a number of carbon atoms ranging from 2 to 6, wherein the alkylene group unit is bonded to the phenylene group unit in at least positions 1 and 4, and wherein at least a portion of the catalytic metal nanoparticles has a particle diameter of not more than 20 nm;
- and wherein the composite structure comprises a substrate and the composite provided on at least a portion of a surface of the substrate.