Thei sostructural compoundso ft he trivalent actinides uranium,neptunium, plutonium, americium,a nd curium with the hydridotris(1-pyrazolyl)borato (Tp) ligand An[h 3-HB(N 2 C 3 H 3) 3 ] 3 (AnTp 3)h ave been obtained through severals ynthetic routes. Structural, spectroscopic(absorption, infrared, laser fluorescence) andm agnetic characterisa-tion of the compounds were performed in combination with crystal field, density functional theory (DFT)a nd relativistic multiconfigurationalc alculations. The covalentb ondingi nteractions were analysed in terms of the natural bond orbital (NBO)a nd quantum theory of atomsi nm olecules (QTAIM) models.