The increasing demand for effective magnetic materials with specific properties encourage research in obtaining new compounds that can be used as molecular magnets at room temperature. Based on the inherent contribution of the d–f electrons and the unique exchange interactions between different metal ions, heterometallic transition metal – lanthanide clusters have received substantial attention in modern chemistry [1]. In the past two decades numerous d-f metal clusters with diverse molecular topologies have been obtained using various synthetic approaches.  This work describes new tetranuclear Fe – Ln (Ln = Pr, Nd) coordination compounds based on 1,1,1 – tris(hydroxymethyl)ethane (thmeH3) ligand. Both compounds were synthetized via hydrothermal method by the reaction of μ-oxo trinuclear iron pivalate, the corresponding lanthanide nitrate, sodium azide and 1,1,1 – tris(hydroxymethyl)ethane ligand in a mixture of methanol and tetrahydrofurane. As result, two compounds with general formula [Fe2Ln2(thme)2(piv)6(MeOH)4] (LnIII = Pr (1), Nd (2)) were obtained. Single crystal X-ray diffraction analysis revealed that both compounds crystalize in the monoclinic P21/c space group with a = 12.0852(8); b = 19.7396(14); c =12.3110(9) Å; V = 2919.4(4) Å3 for 1, and a = 12.1246(7); b = 19.7575(11); c =12.3165(7) Å; V = 2932.6(2) Å3 for 2. Both assemblies (figure) reside on inversion center thus having Ci molecular symmetry and contain a {Fe2Ln2}12+ core, where two FeIII and two LnIII centers are connected via two thme3- ligand with Fe∙∙∙Nd distances of 3.4902(6) Å and 3.5063(6) Å; Fe∙∙∙Pr distances of 3.503(5) Å and 3.517(9) Å and Fe∙∙∙Fe distances of 3.190(2) Å (1) and 3.189(4) Å (2). Metal atoms reside in vertex of parallelogram and are additionally bonded by four pivalate moieties. Bidentate pivalate and two molecules of MeOH complete the coordination sphere of each Ln atom. In both cluster, iron atoms are six-coordinated with a distorted octahedral O6 geometry, being coordinated by four O atoms from two thme3- and two O atoms from two pivalate moieties (Fe-O, 1.987(0) – 2.101(3) Å). Each LnIII (Nd, Pr) atom is nine-coordinated by three O atoms from two thme3- ligands, four O atoms from three pivalates and two O atoms from two MeOH molecules (Nd-O, 2.432(3) - 2.597(3) Å; Pr-O, 2.434(4) - 2.613(1) Å). The spectroscopic and thermal properties of these compounds have also been studied and will be discussed in terms of known structure.