“…[12,20] The theory of the NMR chemical shielding is understood and both ab initio and DFT methods have been used to correlate the experimental chemical shift parameters with structure, conformation, hydrogen bond strength and other molecular properties for numerous compounds. [22][23][24][25][26][27] More recent work has also demonstrated that NMR shifts can reliably predict crystal structures [28][29][30][31] and provide estimates of uncertainties in individual atomicp ositions. [32,33] To understand the nature and strength of the intra-dimer bonding in b and d-[TTF···TCNE] the 13 Cs hift tensors, reported here for the first time, are compared to previously reported benchmark experimental data for TTF, [TTF] 2 2 + + , [19] TCNE, [TCNE] 2 2À ,and [TCNE] 2À .…”