(1,3-Benzothiazol-2-yl) amino-9-(10H)-acridinone derivatives were synthesized via a procedure based on the Ullman reaction and were assessed for their in vitro antileishmanial and anti-HIV activities. Two derivatives, 4-(6-nitro-benzothiazol-2-ylamino)-10H-acridin-9-one and 1-(6-amino-benzothiazol-2-ylamino)-10H-acridin-9-one, revealed a selective antileishmanial activity, mainly due to amastigote-specific toxicity. Results suggested that:the addition of a benzothiazole group on a parent amino-9-(10H)-acridinone ring could enhance antileishmanial abilities, the presence of a 6-amino-benzothiazole group on position 2 amino chain or a 6-nitro-benzothiazole group on position 4 amino chain was essential for specific anti-amastigote properties.