A review is given of the authors' studies on the development of new methods for the synthesis of cationic arene complexes of transition metals. The synthesis in strong protic acids facilitated obtaining pi-arene cations of Mn, Re, Ru, Os, Co, Rh and Ir. New nonacidic methods allowed the set of available cationic arene pi-complexes of Mn, Ru, Rh and pi to be increased considerably. Based on the developed methods a number of previously unknown binuclear organometallic cations are obtained.