An inorganic propellane with central B-B bond

9,10-Dihydroanthracene-9,10-diyl-bridged B-2(NMe2)(2) readily adds [H2NMe2](+), HCl and F3CCOOH across its partial B=N double bond(s), thereby forming mono- or diadducts; treatment with 1-iso-propyl-2-mercaptoimidazole leads to a triply B-B-bridged propellane-like structure.