Simulation technique for the study of the structural properties and supramolecular organization of mesogenic lanthanum(III) complexes with β‐diketones and Lewis bases with the combination of high‐level quantum chemical methods and ab initio molecular dynamics was proposed and approved. Three representatives of La(III) complexes with ligands of various nature were investigated and relations between their structural properties and liquid‐crystalline (LC) behavior were studied. It has been shown that the structure of β‐diketones and their substitutes mostly define the number and type of LC mesophases. The Lewis base ligand generally determines the appearance of LC properties. Estimated anisotropy of geometry values for two complexes were found above the known threshold value defining the presence of LC phases. Thus, these complexes are expected to exhibit LC properties, while the third complex not, which is in agreement with the experimental data. We also used Voronoi–Dirichlet polyhedral (VDP) approach to analyze the first coordination sphere of the La(III) complexes. Calculated parameters of VDP helped to evaluate the forces of intermolecular interactions. The unitless normalized second moment of inertia for three exemplary La(III) complexes was found to correlate with the number of the LC phases of the corresponding complexes.