The synthesis of biphenyl,isomeric methyl-,chloro-,and vitro-biphenyls as well as phenylnaphthalenes has been accomplished in excellent yields by refluxing aromatic primary amines with alkyl nitrite in benzene; an optimum condition for the synthesis of biphenyl is described.Evidence is presented which indicates that the aminoazobenzene is one of the intermediates of the reaction.However,this is not the only route.Study on the reaction under various conditions shows that cou pling of the aromatic diazohydroxide with benzeae ie also possiblo especially in more dilute solutions.Facto support that the aromatic suhstitution here diecussed being proceed by a free radical mechanism.