Polymer materials have rapidly found wide application in engineering as construction materials, chiefly owing to those of properties that make them superior to metals, i.e., their resistance to corrosion, low specific gravity, aesthetic appearance, etc. But polymer materials also have disadvantages that are not shared by metals. Compared to metals, they have lower mechanical strength, relatively low thermal stability, etc. Hence the idea to combine polymers and metals into compounds exhibiting as many advantages of either parent material as possible with the number of their disadvantages reduced to a minimum. Therefore, trials were commenced to fill polymers with dispersed surface-active metals to obtain the so-called metallopolymers, and a large number of synthesis procedures have been developed for obtaining organometallic polymers with metal atoms directly or indirectly linked to carbon in the chain. In this way, materials with valuable properties have been obtained, including typical nonconductors, semiconductors, and conductors, as well as materials having good tensile properties and at the same time being resistant to high temperatures. Some of these materials are also catalysts for quite a number of chemical reactions.