6,9-Dichloro-1,2,3,4-tetrahydroacridine is a synthetic intermediate in the synthesis of tacrine-based acetylcholinesterase (AChE) inhibitors.1It is also an intermediate in the synthesis of multifunctional tacrine hybrids that possess radical scavenging, amyloid-β aggregation inhibitory, and/or β-secretase 1 (BACE1) inhibitory activities in addition to their activity as AChE inhibitors.2,3