Rare-earths are a group of metals with fascinating physical properties and intriguing chemical reactivity. Organometallic rare-earth chemistry is of particular interest because of the increasing number of their applications in industry and consumer goods as well as the importance of understanding their physical and chemical properties. Despite the dominance of the trivalent oxidation state, recently, low-valent organometallic rare-earth compounds were characterized and showed interesting reactivity toward various molecules. The theme of this thesis is the reduction chemistry of rare-earth metal complexes. By utilizing an electronically and geometrically flexible ferrocene diamide ligand (NN^TBS = fc(NSi^tBuMe2)2, fc =1,1'-ferrocenediyl), unprecedented reactivity was discovered together with the synthesis and characterization of a series of rare-earth metal arene complexes. The fruitful reduction chemistry allowed: (1) the discovery of a new aromatic C-H and C-F bond activation mechanism for rare-earths; (2) the synthesis of the first scandium naphthalene complex and a reactivity study on P4 activation by rare-earth arene complexes; (3) the isolation and characterization of a 6C, 10[pi]-electron aromatic system stabilized by coordination to rare-earth metal ions. Recently, an improved method to access paramagnetic rare-earth starting materials for organometallic chemistry was developed in order to study the physical and chemical properties of paramagnetic rare-earth biphenyl complexes.