The reaction of the base-free terminal thorium imido complex [{η5-1,2,4-(Me3C)3C5H2}2ThN(p-tolyl)] ( 1) with p-azidotoluene yielded irreversibly the tetraazametallacyclopentene [{η5-1,2,4-(Me3C)3C5H2}2Th{N( p-tolyl)NNN( p-tolyl)}] ( 2), whereas the bridging imido complex [{[η5-1,2,4-(Me3C)3C5H2]Th(N3)2}2{μ-N( p-tolyl)}2][( n-C4H9)4N]2 ( 3) was isolated from the reaction of 1 with [( n-C4H9)4N]N3. Unexpectedly, upon the treatment of 1 with 9-diazofluorene, the NN bond was cleaved, an N atom was transferred, and the η2-diazenido iminato complex [{η5-1,2,4-(Me3C)3C5H2}2Th{η2-[NN(p-tolyl)]}{N(9-C13H8)}] ( 4) was formed. In contrast, the reaction of 1 with Me3SiCHN2 gave the nitrilimido complex [{η5-1,2,4-(Me3C)3C5H2}2Th{NH( p-tolyl)}{N2CSiMe3}] ( 5), which slowly converted into [{η5-1,2,4-(Me3C)3C5H2}{η5:κ- N-1,2-(Me3C)2-4-CMe2(CH2NNCHSiMe3)C5H2}Th{NH(p-tolyl)}] ( 6) by intramolecular CH bond activation. The experimental results are complemented by density functional theory (DFT) studies. [ABSTRACT FROM AUTHOR]