NEW MATERIAL:The compound of formula I (X is formyl; Y is H or formyl; R1 and R2 are alkyl).

EXAMPLE: The compound of formula IV.

USE: Useful as an intermediate of photo-conductive compound in the fields of information and electronic materials.

PREPARATION: The compound of formula I a can be prepared by (1) reacting the cyclic dithiocalicene derivative of formula II with N,N-dimethylformamide and oxalyl chloride in nitrogen atmosphere at -10W+10°C for several hours, (2) treating the resultant compound of formula III with a perchlorate and then with NaHCO3, and (3) purifying the product by conventional method such as silica gel column treatment.