AbstractBlue‐shifted dihydrogen bonds were predicted to be present in a number of non‐covalent complexes including F3C—H…H—Be—X, F3C—H…H—Mg—X, F3C—H…H4Si, F3Si—H…H—Li, F3Si—H…H—Be—X, F3Si—H…H—Mg—X, and F3Si—H…H4Si (X = H, F, Cl and CH3). Pauli and nuclei–nuclei repulsions between the protonic hydrogen and hydridic hydrogen are proposed as the cause of the blue shift. Copyright © 2004 John Wiley & Sons, Ltd.