Effect of adenosine on the supramolecular architecture and activity of 5-fluorouracil

► The reactions of Ad and 5-XU gave co-crystals in monoclinic with P21 space group. ► With different halo groups at uracil, each structure contains the same type interactions. ► The size of the halo groups on uracil has no effect on the hydrogen bond interaction. ► The antitumor activity of 5-FU against MCF-7 breast cancer decreases in the presence of Ad.