o-Aminophenylarsine is prepared by reduction of o-nitrophenylarsonic acid. Metallation and subsequent treatment with alkyl halides give the secondary o-aminophenylarsines. o-Aminophenylarsines react with aldehydes, ketones and ketoesters forming derivates of the 1,3-benzazarsoline. Exceptions are redox reactions between o-aminophenylarsine and aldehydes. The properties of the compounds are described