Comparison of ion-molecular reactions of free-phenyl cations generated by tritium β -decay with 2-methyl- and 2-phenylquinolines has been investigated. The reaction of direct nitrogen atom phenylation with the help of nucleogenic phenyl cations has been fulfilled for the first time and a new one-step synthesis of tritium-labeled N-phenyl-2-phenylquinolinium salt-lipophilic radioactive biological marker has been elaborated.