Our attempts to synthesise NM intramolecularly coordinated diorganometallic hydrides L2MH2 [M=Si (4), Ge (5), Sn (6)] containing the CH=N imine group (in which L is C,N-chelating ligand {2-[(2,6-iPr2C6H3)N=CH]C6H4}−) yielded 1,1′-bis(2,6-diisopropylphenyl)-2,2′-spriobi[benzo[c][1,2]azasilole] (7), 1,1′-bis(2,6-diisopropylphenyl)-2,2′-spriobi[benzo[c][1,2]azagermole] (8) and C,N-chelated homoleptic stannylene L2Sn (10), respectively. Compounds 7 and 8 are an outcome of a spontaneous double hydrometallation of the two CH=N imine moieties induced by NM intramolecular coordination (M=Si, Ge) in the absence of any catalyst. In contrast, the diorganotin hydride L2SnH2 (6) is redox-unstable and the reduction of the tin centre with the elimination of H2 provided the C,N-chelated homoleptic stannylene L2Sn (10). Compounds 7 and 8 were characterised by NMR spectroscopy and X-ray diffraction analysis. Because the proposed NM intramolecularly coordinated diorganometallic hydrides L2MH2 [M=Si (4), Ge (5), Sn (6)] revealed two different types of reduction reactions, DFT calculations were performed to gain an insight into the structures and bonding of the non-isolable diorganometallic hydrides as well as the products of their subsequent reactions. Furthermore, the thermodynamic profiles of the different reaction pathways with respect to the central metal atom were also investigated.