The crystal structures of 1-chloro-3,3-bis(trifluoromethyl-1λ3,2(1H)-benzoiodoxole (I(hfpp)Cl) and 1-chloro-1λ3, 2-benzoiodoxole-3(1H)-one (I(ba)Cl) are determined. Although the T-shaped molecular structure for I(hfpp)Cl is quite similar to that for I(ba)Cl, the intermolecular interactions including the secondary bondings are significantly different; I(ba)Cl adopts an infinite chain structure with two longer I … O' interactions, whereas I(hfpp)Cl has a dimeric structure with one I … O' secondary bonding. The 127I Mossbauer spectrum for I(hfpp)Cl is quite similar to those of hypervalent iodine(III) compounds having carboxylic and sulfonic ligands and chloride. This shows that the 5p electrons of the iodine(III) atom in I(hfpp)Cl are markedly withdrawn by apical oxygen and chlorine atoms almost equally, suggesting that the alcoholic oxygen atom of the ligand is quite electronegative.