The results of this Letter reveals that the [Re-3(mu-Cl)(3)Cl-9](3-), [Re-3(mu-Br)(3)Br-9](3-), [Re-3(mu-I)(3)I-9](3-) clusters exhibit aromaticity and that spin-orbit effect decreases the aromaticity due to the fact that the 5d3(/2) spinors are more contracted than the scalar 5d orbitals. The [Re-3(mu-I)(3)I-9](3-) and [Re-3(mu-Br)(3)Br-9](3-) clusters are the most aromatic clusters. This can be explained by the np(1/2) and np(3/2) spinors radial expectation (< r >) values which follows the Cl < Br < I sequence. Thus, the most extended spinors correspond to I and Br ligands, as indicated in the ELF plots. Furthermore we carried out TDDFT calculations which agrees with the fact that [Re-3(mu-I)(3)I-9](3-) should show the highest value of aromaticity. (C) 2012 Elsevier B. V. All rights reserved.