7‐Chloro‐1‐(2,6‐di­fluoro­phenyl)‐1H,3H‐thia­zolo­[3,4‐a]­benz­imidazole and 1‐(2,6‐di­fluoro­phenyl)‐6‐methyl‐1H,3H‐thia­zolo­[3,4‐a]­benz­imidazole

The title mol­ecules, C₁₅H₉ClF₂N₂S and C₁₆H₁₂F₂N₂S, respectively, display the well known butterfly‐like conformation with a flat thia­zolobenz­imidazole system. In both compounds, the mean plane through the tricyclic system is almost perpendicular to the 2,6‐di­fluoro­phenyl ring. This arrangement of the aryl group is determined by two intramolecular hydrogen bonds and by an attractive F?S interaction.