A cysmethynil analog that inhibits Icmt with an IC50 value of 0.86 μM; demonstrates nearly 10-fold more potent antiproliferative activity than cysmethynil on human breast cancer MDA-MB-231 cells (IC50s = 2.63 vs. 27.4 μM, respectively) and human prostate cancer PC3 cells (IC50s = 2.55 vs. 25.2 μM, respectively).