The synthesis and structural characterization of hybrid heterocalix [4]arene analogues containing pyrrole, benzene, methoxy-substituted benzene, and pyridine subunits is described. Macrocycles 1 and 2, examples of calix[2]benzene[2]pyrrole and calix[1]benzene[3]pyrrole systems, respectively, are synthesized by the condensation of pyrrole and an appropriate phenylbis(carbinol). Macrocycles 3 and 7, examples of calix[2]benzene[1]pyridine[1]pyrrole and calix[1]pyridine[3]pyrrole, respectively, are synthesized by the use of a carbene-based pyrrole-to-pyridine ringexpansion procedure. Single-crystal X-ray analysis reveals that compounds 1 a, 1 b, and 2 b adopt 1,3-alternate conformations in the solid state, whereas compounds 3 and 7 display structures that are best described as ™flattened partial cones∫ in terms of their conformation. (Series a refers to pure benzenederived systems, whereas series b indicates macrocycles containing 5-methoxyphenyl subunits). In the solid state, the methoxy-functionalized macrocycles 1 b and 2 b, and the chloropyridine-containing macrocycle 7 exist as dimers. In the case of 1 a and 7, these compounds interact with neutral solvent in the solid state. The conformations of the macrocycles in solution were explored by temperature-dependent proton NMR and NOESY spectral analysis. At 188 K, macrocycles 1 a and 2 a adopt flattened 1,3-alternate conformations, whereas macrocycles 3 and 7 exist in the form of flattened partial-cone conformations. Standard proton NMR titration analyses were carried out in the case of macrocycles 1 a and 2 a, and reveal that at least the second of these systems is capable of binding fluoride and chloride anions in CD 2 Cl 2 solution at room temperature (K a 571 and 17 m À1 in the case of 2 a and F À and Cl À , respectively).