The mode of Ti and Sn action of anticancer compounds is still poorly understood. For each octahedral Ti(bzac)2 X2 and Sn(bzac)2 X2 (Hbzac = 1-benzoylacetone) complexes there are five possible isomers. It is not known which of these isomers is responsible for the anticancer activity. One of the Ti complex Ti(bzac)2(OEt)2 whose trade name is budotitane® is a anticancer drug on clinically trial base. Therefore we use VT-NMR (low temperature to high temperature) studies and their crystal structures (1a, 1b, and 2a) to examine their isomerization behavior, conversion rate constant k, and conversion barrier energy £GG‡. We suspect the antitumor activity of Ti and Sn compounds strongly depends on the unsubstituted phenyl rings of the £]-diketonato ligands in the outer sphere of the molecule. If these phenyl rings are replaced by methyl groups, the activity totally disappears. Therefore we propose that the anticancer activity of budotitane may be determined by a DNA intercalating mechanism. We further changed the ligand from Hbzac to FHnpac (FHnpac = 4, 4, 4-trifluoro-1-(naphthalen-3-yl) butane-1, 3-dione) in order to monitor their isomers exchange via 1H NMR. The related crystal structures (1a-NF, 1b-NF, and 2a-NF) were obtained fortunately. The stereochemistry of Ti and Sn complexes as well as their controlling factors is discussed.