Treatment of the dilithiodiphosphide [Li(tmen)]2[C6H4(PPh)2-1,2](tmen =N,N,N′,N′-tetramethylethylenediamine) with (–)-(R,R)- or (+)-(S,S)-Me2C(OCHCH2OSO2C6H4Me-p)2 afforded the enantiomeric chiral diphosphine (+)-(R,R,R*,S*)- or (–)-(S,S,R*,S*)-[C6H4(PPhCH2CHO)2CMe2]-1,2, respectively. Their crystal structures have been determined which show them to be isostructural; hence they are enantiomers rather than diastereoisomers. Thus the original chirality of Me2C(OCHCH2OSO2C6H4Me-p)2 induces a preferred chirality at the P atoms of the product diphosphines. A 1H and 31P NMR spectral study of (+)-(R,R,R*,S*)-[C6H4(PPhCH2CHO)2CMe2]-1,2 has been carried out, involving selective decoupling and nuclear Overhauser experiments, Karplus curves for both 3JHH and 2JPH couplings and ring current shielding effects. This allows assignments to be made of the 31P and non-aromatic 1H signals, and demonstrates that the structure determined by X-ray crystallography in the solid state is not significantly changed in solution.