A series of biphenol-derived quaternary ammonium salts, originally developed as DNA-cross-linking agents, and carrying either two (i.e., 1) or four (i.e., 2) net positive charges, were investigated for their in vitro DNA-transcription- and acetylcholinesterase (AChE)-inhibitory activities. The effects of charge and type of linker between the two phenolic residues were systematically investigated. Several compounds showed good activities in both tests, which makes them potential lead candidates for drug design.