Diphosphene compounds usually exhibit a symmetry-allowed () (intense) and symmetry-forbidden electronic transitions () (weak). In Raman, there is significant enhancement of P=P stretch in the resonance with allowed electron  transition than with the forbidden  transition due to different geometries of excited states and enhancement mechanism.  Also the observed strong Raman shifts for and  suggest stronger dipnictenes feature of diphosphene compared with P-P single bond.