Rotational spectra of the symmetric-top complexes 14N2···ICF3 and 15N2···ICF3 were observed and analysed to give rotational constants B0, centrifugal distortion constants DJ and DJK, and nuclear quadrupole coupling constants χaa(X). Significantly different values of χaa(14Ni) and χaa(14No) establish chemical inequivalence of the two 14N nuclei and an average zero-point oscillation angle of 19.8(5)° for the N2 subunit. A distance rN···I, = 3.441(1) Å only slightly shorter than the sum of the N and I van der Waals radii, a small intermolecular stretching force constant kσ,=2.94 N m-1 and negligible charge redistribution on complex formation demonstrate the presence of a weak halogen bond.