Amyloid-beta, metal ions, and reactive oxygen species are linked to the pathology of Alzheimer's disease (AD). To identify their roles in the pathology of AD and control their pathological reactivities, various chemical tools have been developed. The redox-based strategy for designing small molecules with multiple reactivities toward pathogenic factors has recently received significant attention. This Account briefly illustrates our current understanding of diverse pathological elements associated with AD and their redox properties. Furthermore, we summarize some examples of redox-active small molecules with multifunctionality that were constructed by tuning electronic properties through incorporating substituents onto the backbones.