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Three new compounds, namely, 5‐fluorocytosine–urea (2/1), 2C4H4FN3O·CH4N2O, (I), 5‐fluorocytosine–5‐fluorocytosinium 3,5‐dinitrosalicylate–water (2/1/1), 2C4H4FN3O·C4H5FN3O+·C7H2N2O7−·H2O, (II), and 2‐amino‐4‐chloro‐6‐methylpyrimidine–6‐chloronicotinic acid (1/1), C6H4ClNO2·C5H6ClN3, (III), have been synthesized and characterized by single‐crystal X‐ray diffraction. In compound (I), 5‐fluorocytosine (5FC) molecules A and B form two different homosynthons [R22(8) ring motif], one formed via N—H...O hydrogen bonds and the second via N—H...N hydrogen bonds. In addition to this interaction, a sequence of fused‐ring motifs [R21(6), R33(8), R22(8), R43(10) and R22(8)] are formed, generating a supramolecular ladder‐like hydrogen‐bonded pattern. In compound (II), 5FC and 5‐fluorocytosinium are linked by triple hydrogen bonds, generating two fused‐ring motifs [R22(8)]. The neutral 5FC and protonated 5‐fluorocytosinum cation form a dimeric synthon [R22(8) ring motif] via N—H...O and N—H...N hydrogen bonds. On either side of the dimeric synthon, the neutral 5FC, 5‐fluorocytosinium cation, 3,5‐dinitrosalicylate anion and water molecule are hydrogen bonded through N—H...O, N—H...N, N—H...OW and OW—HW...O hydrogen bonds, forming a large ring motif [R1010(56)], leading to a three‐dimensional supramolecular network. In compound (III), 2‐amino‐4‐chloro‐6‐methylpyrimidine (ACP) interacts with the carboxylic acid group of 6‐chloronicotinic acid via N—H...O and O—H...O hydrogen bonds, generating an R22(8) primary ring motif. Furthermore, the ACP molecules form a base pair via N—H...N hydrogen bonds. The primary motif and base pair combine to form tetrameric units, which are further connected by Cl...Cl interactions. In addition to this hydrogen‐bonding interaction, compounds (I) and (III) are further enriched by π–π stacking interactions. [ABSTRACT FROM AUTHOR]