Conjugated polymers are semiconducting materials and an integral component of solar cells and other optoelectronic gadgets, which are important as environment-friendly devices. Conjugated polymers are less expensive than inorganic materials and are easy to process, hence several synthetic methods have been developed based on transition metal-catalyzed polycondensation involving sp 2 -sp 2 C–C bond formation for their production. The coupling reaction between monomers involves the following steps: (a) metal-catalyzed oxidative addition (as presented in Chapter 1) across the C–X bond of the monomer; (b) transmetallation with a main group organometallic compound; and (c) reductive elimination (as presented in Chapter 1) yielding the C–C bond formation and regeneration of the active catalyst, which are typical in a C–C bond formation catalyzed by organometallic complex (Figure 7.1). 1 The reactions are characterized by mild conditions, tolerance to many functional groups, and possibility of synthesizing regioregular polymers.