To obtain a new diazonium salt useful as a chromophoric component of a photo-sensitive and heat-sensitive recording material having a specific group as a 4th-site amino group.

This diazonium salt is expressed by formula I (R1 to R4 are each H, an alkyl, an aryl, etc.; R5 to R7 are each H, an alkyl, an alkoxy, etc.; R8 to R11 are each H, an alkyl, an alkoxy, a halogen, etc.; X is an anion), e.g. a compound of formula II. The compound of the formula I is obtained by diazotizing corresponding aniline in an acidic solvent by using sodium nitrite, nitrosylsulfuric acid, isoamyl nitrite, etc. Because a maximum absorbing wavelength (λmax) exists in a longer wavelength side than 400 nm, the heat-sensitive recording material can be fixed by a light source of visible light having a wavelength longer than 400 nm. The diazonium salt can also be stabilized by forming a complex compound by using zinc chloride, cadmium chloride, tin chloride, etc.