Coumarilic acid is reacted with N-benzylpiperazine (II) by two different ways: a) The acid chloride (I) is treated with (II) in the presence of a further base to give (III) or without a base in boiling dimethylformamide. b) The coumarilic acid salt of N-benzylpiperazine (IV) is converted to (III) by heating up to 170-250 C.