To obtain the subject new compound useful as an organic photoconductor, especially a charge-transferring material for an electrophotographic photoreceptor, electroluminescent element, etc., or a production intermediate for a luminescent material, etc.

This dialdehyde compound is expressed by formula I [R1 to R10 are each H, a halogen, a dialkylamine or the like; X is a 1-4C alkylene or a (substituted) 6-18C arylene], e.g. an aldehyde compound of formula II. A compound of formula I is obtained by formulating a vinyl compound of formula III (e.g. 1,4-bis[1-(p-methylphenyl)vinyl]benzene) using a Vilsmeier reagent which has been prepared by the reaction of a formamide compound of formula IV [R11 and R12 are each a lower alkyl or a (substituted) aryl] (e.g. N,N'-dimethylformamide) with a halogenating reagent in the theoretical amount to the vinyl compound, preferably one or more mol equivalent to one vinyl group, in an organic solvent (e.g. toluene), and hydrolyzing the resultant immonium salt with an alkali (e.g. sodium hydroxide).