PURPOSE: To provide a novel trisubstd. benzoyl cyanide which is useful as an intermediate of a herbicide, 2-(2,3,4-trisubstd. benzoyl)-1,3-cyclohexanediones.

CONSTITUTION: This trisubstituted benzoic acid intermediate is a compd. represented by formula I (wherein R6 represents H, 1-4C alkoxy or 1-4C alkyl; (n) is 0 or 2; and R7 represents 1-6C alkyl). The compd. is obtd. by reacting a compd. represented by formula II with oxazalyl chloride to conduct acid chlorination, thereby obtaining a compd. represented by formula III, and reacting the compd. with cuprous cyanide to conduct acid cyanidation. The compd. represented by formula I is reacted with a dione represented by formula IV (wherein R and R1 to R5 each represents H or 1-4C alkyl) to obtain a 2-(2,3,4- trisubstd. benzoyl)-1,3-cyclohexanedione compd. represented by formula V.