Furosemide (Fur) is a BCS class IV diuretic drug with low bioavailability due to its poor solubility and poor membrane permeability. Triamterene (Tri) is a potassium‐sparing diuretic with low bioavailability due to its poor solubility. Here, a novel drug–drug salt composed of Tri and Fur was successfully synthesized. Tri–Fur was comprehensively characterized with single‐crystal X‐ray and powder X‐ray diffraction techniques, thermogravimetric analysis, differential scanning calorimetry and dynamic vapor sorption. The apparent equilibrium solubility (in pH 2.0 buffer) of Tri–Fur is improved compared with Fur and a physical mixture of Tri with equimolar Fur by 15.3‐fold and 12.2‐fold enhancements, respectively. Its intrinsic dissolution rate (in pH 2.0 buffer) is also higher than for a Fur component with an enhancement of 9.5‐fold. This study provides a valuable insight into the formation of dual pharmaceutical salts and demonstrates that Tri–Fur can be a potential alternative formulation.