The study of Magnetic Ionic Liquids (MILs) has been a new and emergent field since 2005. These materials allow physicochemical properties (viscosity, melting point, chemical stability, high ion conductivity, etc.) to be controlled by external magnetic fields [1]. During these last few years the synthesis, study and application of these smart materials has increased exponentially [2], being necessary to provide a complete picture of their crystal structure and main magnetic interactions in play. It was generally assumed that magnetic interactions were negligible in MILs, so they were not expected to exhibit 3D ordering [3]. However, we have found that it is possible to synthetize MILs with three-dimensional ordering, which opens up new fields of understanding and improving the magnetic couplings within MILs in their condensed phases [4]. Thus, the question about cooperative magnetic effects, complex anion interaction, and magnetostructural correlation is quite important and it is actually in focus of materials science. These aspects could be explained connecting experimental studies (magnetic and X-Ray and neutron powder diffraction) and first-principle based theoretical methods.