Furosemide is an important pharmaceutical, listed in the World Health Organization's List of Essential Medicines, primarily used in relieving fluid accumulation (edema) in the heart, liver or kidney. Cocrystallisation of furosemide has been widely investigated as a route to improving its relatively poor aqueous solubility. Under its synthesis conditions, described in section 1 of the Supplementary Information, the furosemide picolinamide co-crystal readily forms a solvate phase.