The 2 lower-rim functionalized biscalix[4]arenes, 2,2'-bis-[5,11, 17,23-tetra-tert-butyl-25,26,27-trihydroxycalix [4] arenyloxy] diethyl ether and 1, 3-bis-[5,11,17,23-tetra-tert-butyl-25,26,27-trihydroxycalix[4]arenyloxyl propanone have been converted to their ester and ketone derivatives. The complexation properties of the synthesized ionophores toward selected alkali and transition metal cations are reported. Hexaester derivatives of 2,2'-bis-[5,11,17,2 3-tetra-tert-butyl-25,26,27-trihydroxycalix[4]arenyloxyl] diethyl ether and 1,3-bis-[5,11,17,23-tetra-tert-butyl-25,26,27-trihydroxycalix[4]arenyloxyl propanone are not selective but are good extractants for all of the metal ions studied. However, the 2,2-bis-[5,11,17,23-tetra-tert-butyl-25,26,27-trihydroxycalix[4]arenyloxyl diethyl ether and 1,3-bis-[5,11,17,23-tetra-tert-butyl-25,26,27-trihydroxycalix[4]arenyloxyl propanone as well as their hexaketone derivatives extract Hg2+ selectively. We deduced that these ligands display high selectivities that depend on different factors, such as the conformation, polarizability, and the nature of the substituents on the lower rim of the biscalixarenes.