Treatment of (η5-C5Me5)2ThMe2 (1) with p-tolylNH2 in toluene, in the presence of 4-dimethylaminopyridine (dmap), affords a Lewis base-supported terminal thorium imido metallocene, (η5-C5Me5)2Th═N(p-tolyl)(dmap)2 (5), alongside the release of methane. In toluene solution, an equilibrium is established among complex 5, dmap, and the amido pyridyl complex (η5-C5Me5)2Th[NH(p-tolyl)][κ2-C,N-4-(Me2N)C5H3N] (5'), setting the stage for diverse reactivity. Complex 5 may initiate [2 + 2], [2 + 4], [2 + 1], or [2 + 3] cycloadditions with elemental sulfur and selenium, alkynes, carbodiimides, ketones, thio-ketones, isothiocyanates, CS2, organic nitriles and isonitriles, as well as organic azides. Moreover, imido moiety can act as a nucleophile toward metal halides, esters, and azidosilanes; and it may promote deprotonation reactions with 1-methylimidazole, 2,6-Me2C5H3NO, Me3PO, silanes, amidate PhCONH(p-tolyl), and nitriles (PhCH2CN and Ph2CHCN). Notably, reaction of 5 with Me3SiCHN2 forms the bimetallic complex [(η5-C5Me5)2Th]2(μ-N═NN═CSiMe3)2 (44) with toluene elimination. In contrast, complex 5' undergoes reactions with elemental selenium and tellurium, PhSiH2Cl, organic isonitriles (2,6-Me2C6H3NC, Me3CNC, and C6H11NC), and organic azides (p-tolylN3 and Ph3CN3) to afford amido selenido, amido tellurido, chloro pyridyl, amido pyridyl, amido alkenyl, and bis-amido complexes, respectively. Furthermore, a comparison with related terminal imido thorium metallocenes illustrates how substituent effects on the cyclopentadienyl and imido ligands influence the reactivity of these molecules.