AbstractThe α‐addition of immonium ions and anions (OH−, SeH−, S2O3 2−, N3− NCO− NCS−, RCO2 −, ROCO2−) to isonitriles, accompanied by secondary reactions provides a means for the one‐stage synthesis of organic nitrogen compounds starting with two to five different components. Thus, by the condensations of amines (ammonia, primary, and secondary aliphatic and aromatic amines, hydrazines) and aldehydes or ketones with isonitriles and acids, a number of α‐aminocarboxylic acid amides, thioamides, selenoamides, 1,5‐disubstituted retrazoles, hydantoin imides, thiohydantoin imides, α‐acylamino carboxylic acid amides, oligopeptide derivatives, β‐lactams, derivatives of penicillanic acid, urethanes, diacylimides, and various hydrazine derivatives, can be prepared. The reactions are easily carried out and take place under mild conditions. Yields of more than 90% are frequently encountered.