PURPOSE: To obtain a new azo-based compound, having high sensitivity and improved in light stability by introducing the structure of chrysene which is a quencher into the molecule of the azo-based compound and a new diazonium salt as an intermediate suitable for its production.

CONSTITUTION: An azo-based compound expressed by formula I (A is coupler residue), e.g. a compound expressed by formula III and a diazonium salt expressed by formula II (X is anion) which is an intermediate for the compound. The compound expressed by formula I, e.g. a compound expressed by formula Ia is obtained by dropping sodium nitrite or nitrous acid into an acidic aqueous solution of an amine-based compound expressed by formula IV at a low temperature while stirring the acidic aqueous solution, then adding an acid to be an origin of the anion (X), providing a crystallized new tetrazonium salt expressed by formula IIa, subsequently adding a prescribed amount of a coupler expressed by the formula HA to the resultant tetrazonium salt in an organic solvent and carrying out coupling reaction.