Abstract: In a previous paper we have described the synthesis and biological evaluation of some m-(alkylamino) alkoxyphenyl N, N-dimethylcarbamates. One of these compounds, CUI XING AN, is now used as an analeptic for Chinese traditional herbal anesthesia. In order to search for further anticholinesterases with higher activity on the CNS, a number of thio-analogues of the above series were synthesized. Several of these compounds were found to have much higher anticholinesterase activity than the corresponding oxygen analogues, among which m-(2-diethylamino)-ethylthiophenyl-N, N-dimethylcarbamate (Ⅱ₂) was shown to be the most active. Compound Ⅱ₂ exhibited a longer duration of action in animal experiments than CUI XING AN.