Antileukemic activities of more than 30 2,5-bis(1-aziridinyl)-p-benzoquinones (4) were correlated against well-defined physicochemical constants. These compounds were evaluated against lymphoid leukemia L1210 in BDF1 mice. The best equations obtained exhibited a linear dependence on the hydrophobic constant, pi. Characteristic aspects of the equations are that the larger the relative hydrophilicity of the drugs the stronger the antileukemic activity will be and that the more hydrophilic compounds have a greater chemotherapeutic index. Steric and electronic effects were also determined to be important. Based on the correlations, three compounds (11, 15 and 19) were designed, synthesized, and biologically evaluated.