The reactivity of the organic-substituted arsanylborane tBuAsHBH2NMe3 (1) towards different elemental chalcogenes as well as organic oxidants such as O-NMe3, Me3Si􀀀 O􀀀 O-SiMe3, MesCNO and cyclohexenesulfide is reported. By the reaction of 1 with grey selenium, the selenium oxidation product tBuAs(Se)HBH2NMe3 (2) was obtained. For the oxidation with sulfur, the two products tBuAs(S)HBH2NMe3 (3a) and tBuAs(S)SHBH2NMe3 (3b) could be isolated as oils. The structural characterization of As(tBuAs(S)SHBH2NMe3)3 (4) as well as corresponding DFT computations allow insights into the decomposition behavior of 3a and 3b in solution. For the reaction of MesCNO with 1, the formation of an unusual As􀀀 H activation product Mes-C(NOH)-AstBu-BH2NMe3 (5) is observed. In the reaction with Me3N􀀀 O, the first isolatable oxo-arsanylboranes tBuAs(O)HBH2NMe3 (6a) and tBuAs(O)OHBH2NMe3 (6b) are obtained, with 6b also being accessible via the controlled reaction of 1 with air.