PURPOSE: To suppress the formation of by-products such as unclearly chlorinated substances, etc., and produce high-purity naphthalendicarbonyl dichloride in good yield according to simple operation.

CONSTITUTION: This method for producing naphthalendicarbonyl dichloride is to make dimethyl naphthalendicarboxylate react with chlorine gas while irradiating the dimethyl naphthalendicarboxylate with ultraviolet rays. In this method, the reaction is carried out in the presence of an etherified compound, an acid amide compound or an aromatic carbonyl compound. The isolation and purification of the naphthalendicarbonyl dichloride from the reactional product are readily carried out and this method is extremely industrially advantageous.