Good linear correlations between GIAO-MP2 calculated B-11 NMR chemical shifts of boronium-onium cations 1a-h and C-13 NMR chemical shift of the corresponding isoelectronic carbonium-onium dications 2a-h as well as between Al-27 NMR chemical shifts of the alonium-onium cations 3a-h and the Si-29 NMR chemical shifts of the corresponding isoelectronic siliconium-onium dications 4a-h were found. The close relationship demonstrates that the same factors that determine the chemical shifts of the boron and aluminum nuclei also govern the chemical shifts of the carbon and silicon nuclei, respectively, within the hypercoordinate onium compounds. On the other hand, no correlation exists between C-13 NMR chemical shifts of carbonium-onium dications 2a-h and the Si-29 NMR chemical shifts of the corresponding siliconium-onium dications 4a-h. Furthermore, no correlation was found between B-11 NMR chemical shifts of boronium-onium cations 1a-h and Al-27 NMR chemical shifts of the corresponding alonium-onium cations 3a-h.