The reactions of titanium alkoxides with a large excess of different carboxylic acids under nonhydrolytic conditions leads to the reproducible formation of well-defined nano-building units (NBUs) with the formula [Ti8O8(OOCR)16] [R = C6H5, C(CH3)3, CH3]. The structures of these titanium–oxo–carboxylate clusters have been determined by crossing different characterization techniques and methodologies (single-crystal X-ray diffraction, and 13C and 1H solid state NMR spectroscopy). The solubility and transferability of these clusters in common solvents can be tuned by selecting the nature of the organic ligand. Indeed, a robust post-modification of the carboxylate ligands can be done by trans- esterification reactions on the titanium–oxo clusters. These reactions keep the integrity of the octameric titanium–oxo core intact, while completely exchanging the organic shell of the cluster. In this study, one- and two-dimensional solid state NMR and relaxation measurements have been highly complementary to the thermal agitation obtained by crystallography. It has also been evidenced that entrapping of small molecules can be easily done. This is an interesting feature for storage and catalysis.