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2,3,5,6-Tetramethyl-1,4-diisocyanobenzene (<b>1</b>), 1,4-diisocyanobenzene (<b>2</b>), and 1,4-dicyanobenzene (<b>3</b>) were co-crystallized with 1,3,5-triiodotrifluorobenzene (1,3,5-FIB) to give three cocrystals, <b>1</b>·1,3,5-FIB, <b>2</b>·2(1,3,5-FIB), and <b>3</b>·2(1,3,5-FIB), which were studied by X-ray diffraction. A common feature of the three structures is the presence of I···C_isocyanide or I···N_nitrile halogen bonds (HaBs), which occurs between an iodine σ-hole and the isocyanide C-(or the nitrile N-) atom. The diisocyanide and dinitrile cocrystals <b>2</b>·2(1,3,5-FIB) and <b>3</b>·2(1,3,5-FIB) are isostructural, thus providing a basis for accurate comparison of the two types of noncovalent linkages of C≡N/N≡C groups in the composition of structurally similar entities and in one crystal environment. The bonding situation was studied by a set of theoretical methods. Diisocyanides are more nucleophilic than the dinitrile and they exhibit stronger binding to 1,3,5-FIB. In all structures, the HaBs are mostly determined by the electrostatic interactions, but the dispersion and induction components also provide a noticeable contribution and make the HaBs attractive. Charge transfer has a small contribution (<5%) to the HaB and it is higher for the diisocyanide than for the dinitrile systems. At the same time, diisocyanide and dinitrile structures exhibit typical electron-donor and π-acceptor properties in relation to the HaB donor.