Poly(p-phenylene) PPP is one of the most fundamental π-conjugated polymers and has long attracted the interest of organic, theoretical and polymer scientists. PPP is synthesized by various methods including (a) oxidizing polymerization of benzene with CuCl2 and AlCl3, (b) aromatization of poly(cyclohexadiene)s and (c) dehalogenative organometallic polymerization of 1,4-dihalobenzene. Recent development of organometallic chemistry makes it possible to prepare a variety of PPPs having side chains and side rings. This chapter deals with the preparation of PPP, its related polymers and PPPs with side chains and side rings. A brief discussion about the mechanism of organometallic polymerization is also included.