N-Nitroso Varenicline is primarily of concern due to its potential formation as a nitrosamine impurity in pharmaceutical products containing varenicline, an active ingredient used to aid smoking cessation. Nitrosamine impurities like N-Nitroso Varenicline are classified as probable human carcinogens based on animal studies, raising significant safety and regulatory concerns. As such, its main relevance lies in quality control and risk assessment during drug manufacturing. Regulatory agencies require strict limits on its presence in medications, prompting manufacturers to implement sensitive analytical methods to detect and control trace levels. Efforts are focused on minimizing formation during synthesis and storage, particularly under conditions where nitrosating agents may be present. Its application, therefore, is not functional but rather a critical consideration in pharmaceutical safety and compliance.