A missing family of the extremely air sensitive tripentelyltrielanes was discovered. Their stabilisation was achieved by using the bulky NHC IDipp (NHC=N-heterocyclic carbene, IDipp=1,3-bis(2,6-diisopropylphenyl)-imidazolin-2-ylidene). The tripentelylgallanes and tripentelylalanes IDipp center dot Ga(PH2)(3) (1 a), IDipp center dot Ga(AsH2)(3) (1 b), IDipp center dot Al(PH2)(3) (2 a) and IDipp center dot Al(AsH2)(3) (2 b) were synthesised by salt metathesis of IDipp center dot ECl3 (E=Al, Ga, In) with alkali metal pnictogenides such as NaPH2/LiPH2 center dot DME and KAsH2, respectively. Moreover, the detection of the first NHC-stabilised tripentelylindiumane IDipp center dot In(PH2)(3) (3) was possible by multinuclear NMR spectroscopy. Initial investigations of the coordination ability of these compounds resulted in the successful isolation of the coordination compound [IDipp center dot Ga(PH2)(2)(mu(3)-PH2{HgC6F4}(3))] (4) by reaction of 1 a with (HgC6F4)(3). The compounds were characterised by multinuclear NMR spectroscopy as well as single crystal X-ray diffraction studies. Supporting computational studies highlight the electronic features of the products.