SARS-CoV-2, influenza, RSV, HCV, and yellow fever viruses continue to present serious global health threats, highlighting the urgent need for broadly active, affordable, and easily synthesised antiviral drugs. We will present bisartans, a new class of potent sartans, engineered with anionic carboxylate or tetrazole groups to specifically target shared molecular features across multiple viruses. The negative charge of the tetrazole group allows bisartans to form strong interactions with cationic arginine residues and metal ions within essential viral and host receptors, such as the SARS-CoV-2 ACE2 receptor, influenza neuraminidase, and RSV fusion protein. Computational modelling and laboratory experiments confirmed that bisartans and their analogues bind tightly and selectively to viral catalytic domains, offering a clear mechanism for broad-spectrum activity. Notably, the compounds displayed more stable binding and higher affinity for key viral targets than FDA-approved anti-viral drugs. Further biological assays consistently demonstrated that these compounds actively inhibit a range of respiratory and non-respiratory viruses, with favourable selectivity indexes. In summary, bisartans are highly promising candidates for the development of pan-antiviral therapies that can be rapidly used during future outbreaks.