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The reactions of [Ti(η⁵-Ind)(NMe2)2Me], [Ti(η⁵-Ind)(NMe2)Cl2], and [Zr(η⁵-Ind)(NMe2)2Cl] with 2,6-dimethylphenyl isocyanide (CN(2,6-Me2Ph)) and tert-butyl isocyanide (CN-t-Bu) have been investigated. For the first complex, insertion occurs exclusively into the Ti−C bond to give [Ti(η⁵-Ind)(NMe2)2{C(Me)&dbd;N-t-Bu}] (1), which, according to DFT results, is due to the weakness of the Ti−CH3 bond when compared to Ti−NR2. [Ti(η⁵-Ind)(NMe2)Cl2] was found to react with 1 equiv of CN(2,6-Me2Ph) to yield [Ti(η⁵-Ind){C(NMe2)&dbd;N(2,6-Me2Ph)}Cl2] (2). Two equivalents of 2,6-dimethylphenyl isocyanide reacts with [Zr(η⁵-Ind)(NMe2)2Cl] to give the double insertion compound [Zr(η⁵-Ind){C(NMe2)&dbd;N(2,6-Me2Ph)}2Cl] (3). The same reaction performed with CN-t-Bu proceeds slowly and enabled the characterization, by NMR, of [Zr(η⁵-Ind)(NMe2){C(NMe2)&dbd;N-t-Bu}Cl] (4) and [Zr(η⁵-Ind){C(NMe2)&dbd;N-t-Bu}2Cl] (5). The molecular structures of 2 and 3 have been determined by X-ray diffraction. DFT calculations of the insertion of CNH in the zirconium nitrogen bonds of [Zr(η⁵-Ind)(NR2)2Cl] (R = H, Me) have been performed and show that the progressive stability of the insertion products accounts for the experimentally found double insertion product.