The synthesis and characterization of the unprecedented compounds IDipp⋅E′H2AsH2 (E′=Al, Ga; IDipp=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene) are reported, the first monomeric, parent representatives of an arsanylalane and arsanylgallane, respectively, stabilized only by a LB (LB=Lewis Base). They are prepared by a salt metathesis reaction of KAsH2 with IDipp⋅E′H2Cl (E′=Al, Ga). The H2‐elimination pathway through the reaction of AsH3 with IDipp⋅E′H3 (E′=Al, Ga) was found to be a possible synthetic route with some disadvantages compared to the salt metathesis reaction. The corresponding organo‐substituted compounds IDipp⋅GaH2AsPh2 (1) and IDipp⋅AlH2AsPh2 (2) were obtained by the reaction of KAsPh2 with IDipp⋅E′H2Cl (E′=Al, Ga). The novel branched parent compounds IDipp⋅E′H(EH2)2 (E′=Al, Ga; E=P, As) were synthesized by salt metathesis reactions starting from IDipp⋅E′HCl2 (E′=Al, Ga). Supporting DFT computations give insight into the different synthetic pathways and the stability of the products.