Abstract: A diazonium salt represented by the following general formula (1) and a thermal recording material using the diazonium salt: General Formula (1) wherein R1 and R2 each independently represents an alkyl group, an aryl group, an acyl group, an alkoxycarbonyl group or a carbamoyl group, and R1 and R2 may be linked each other to form a ring; and R3 to R6 each independently represents a hydrogen atom, a hydroxyl group, a halogen atom, an alkyl group, an aryl group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, an alkylsulfonyl group, an arylsulfonyl group or a diazonio group, and at least one of R3, R4, R5 and R6 represents the diazonio group.

Abstract: A heat-sensitive recording material including a substrate having disposed thereon a heat-sensitive recording layer containing a diazo compound and a coupler compound capable of reacting with the diazo compound to develop color,