NEW MATERIAL:A compound of formula I (R1, R2 are H, alkyl, aryl, aralkyl, heterocyclic, or incorporate to form a ring; R3 is alkyl, aralkyl, alkoxy, aryl, formula II; R4 is H, alkyl, alkoxy, aralkyl, aryl).

USE: An electric charge transfer material. The photo-sensitive substance containing the same has high sensitivity, reduced fatigue deterioration by residual potential and repeated use, high stability to light with duration.

PREPARATION: The reaction of a phosphorus compound of formula III [X is -P+(R5)3Y- (R5 is alkyl, aryl; Y is halogen ion), PO(OR6)2 (R6 is alkyl)] with a diformyl compound of formula IV is carried out in an inert solvent in the presence of a condensation reagent to give the compound of formula I.