We report about the spin-orbit effects on the aromaticity of the B-4(2-), Al-4(2-), In-4(2-) and Tl-4(2-) clusters via the magnetically-induced current density method. All-electron density functional theory (DFF) calculations were carried out using the four-component Dirac-Coulomb (DC) Hamiltonian, including scalar and spin-orbit relativistic effects. The relativistic values for ring current strengths were obtained by numerical integration over the current flow. These values were compared to the scalar relativistic and non-relativistic values, in order to assess the corresponding contributions to aromaticity. It was found that in the heavy cluster, TI42-, there is a significant influence of both scalar and spin-orbit relativistic effects. (C) 2017 Elsevier B.V. All rights reserved.