The invention relates to antibody drug conjugate (ADC) compounds represented by Formula I: Ab-(L-D)p I where one or more 1,8 bis-naphthalimide drug moieties (D) having Formulas IIa and IIb are covalently linked by a linker (L) to an antibody (Ab). The invention also relates to pharmaceutical compositions comprising an effective amount of a Formula I ADC for treatment of hyperproliferative disorders and other disorders. The invention also relates to methods for killing or inhibiting the multiplication of a tumor cell or cancer cell including administering to a patient an effective amount of a Formula I ADC.