The lab made an effort to prepare some biological active cantharidinimines by heating the reactant 1 and 2a–g, 5h–i and 7j–r amines to suitable temperature with ethanol to provide 18 N-thiazolyl-, sulfanyl-, aminopyridyl-, bromopyridyl-, alkylpyridyl- and hydroxypyridylcantharidinimines 3a–g, 4a–c, 6h–i and 8j–r in yield of 4–77% (Chart 1). These cantharidinimine derivatives were tested for their capabilities to suppress growth of the human carcinoma cell lines, HL-60, MCF7, Neuro-2a and A549, because the incidence rate is more prominent in Asian countries than western countries. Compounds 3c–d and 6h–i were found to have some antitumor activity in HL-60 but less activity in MCF cell and compounds 8j–l displayed some inhibition effects to A549 cell line, but less effect to Neuro-2a cell line. Compounds 8m–r had no cytotoxic effect against both cell lines. The cytotoxic effects of these cantharidinimine compounds seemed to be better than the cantharidinimide compounds which we had mentioned several years ago.