AbstractReactions of GaX3(X  Br, I) with As(SiMe3)3in 1:1 and 2:1 mole ratios were investigated. For the latter reactant stoichiometry, substances having the empirical formulae AsBr3Ga2(1) and Asl3Ga2(2), the analogues of the previously reported single‐source GaAs precursor (AsCl3Ga2)n, were isolated as yellow isolated as yellow insoluble powders. Low‐temperature reactions in a 1:1 mole ratio resulted in the isolation of the adducts Br3Ga.As(SiMe3)3(3) and I3Ga.As(SiMe3)3(4). On the other hand, at room temperature the GaBr3reaction resulted in a complex mixture from which no characterizable compounds were isolated, whereas the Gal3reaction afforded the crystalline compound [I2GaAs(SiMe3)2]2(5). The structures of 4 and 5 were elucidated by complete single‐crystal X‐ray analysis (crystal data: 4, monoclinic, space groupP21/c,a= 16.497(2) Å,b= 9.629(1) Å,c= 16.658(2) Å, β = 113.21(1)°,V= 2432(1) Å3,Z= 4; 5, orthorhombic, space groupPbca, a= 14.279(2) Å,b= 17.509(2) Å,c= 13.818(2), Å,V