Some 2,3-bis(substituted methyl)naphthazarins and related compounds were synthesized by the Diels-Alder reaction of benzoquinone and 2,3-dimethylbutadiene followed by oxidation and substitution reactions. These compounds were prepared as potential biological alkylating agents. Screening results indicated that 1,4-diacetyl-6,7-dimethyl-4a,5,8,8a-tetrahydronaphthalene and 5,8-bis(benzoyloxy)-2,3-dimethyl-1,4-naphthoquinone possessed borderline activity against leukemia P388 and that naphthazarin diacetate possessed confirmed cytotoxicity against the cell culture of human epidermoid carcinoma of the nasopharynx.