Pyrogallolarenes are tetrameric macrocycles that form from 1,2,3-trihydroxybenzene and aldehydes under acidic conditions. When 2-ethylbutanal or 2-propyl-pentanal was so treated, the branched-chain pyrogallolarenes crystallized as nanotubes or bilayers, respectively. When the behavior of each compound was assessed by using the planar bilayer conductance method, pore formation was observed. The properties of the pores were significantly different from each other, probably reflecting different types of pore organization within the membrane.