A review with 356 refs. on the wide variety of transition metal-centered conjugated/conducting polymers and networks. Organometallic-based systems, such as organometallic acetylenic polymers, metallacycle polymers, polyferrocenylenes, transition metal aryl complexes, pendant organometallic polymers, pendant ferrocene polymers, organometallic coordination polymers, as well as various types of coordination complexes, such as one-dimensional and two-dimensional phthalocyanine polymers, conjugated porphyrin polymers, polymers derived from schiff-base complexes, polymeric bipyridine and related complexes, and diisocyanoaryl ligands are described. [on SciFinder(R)]