Both optical and scanning electron microscope (SEM) imaging showed the formation of well-defined hexagonal prisms having a high monodispersity (length = 112 ± 10 m for 55 crystals) (Figure ). Single crystal X-ray diffraction showed a structure belonging to the chiral hexagonal 622 crystal system with the rare space group P622 (Figure ). Hexagonal plates were also observed as a minor product (<2%) (Figure ). Single crystal X-ray diffraction studies revealed that the prisms and the plates have the same crystallographic structure (Figure , Table ). The phase purity was confirmed by fitting the measured powder X-ray diffraction (PXRD) diffraction patterns of bulk samples with one simulated from the crystal structure (Figure ). These crystals are part of our series of isostructural, chiral metal-organic frameworks grown from achiral components . The propellor-type arrangement of four coordinated pyridine units from four different ligands around the bivalent cadmium cations imparts a chiral arrangement on both the coordination nodes and the channels. Two types of channels are positioned in parallel along the c-axis, , one hexagonal-type centered around the 6-fold axes and the trigonal-type centered around the crystallographic 3-fold axis. The inner walls of the two types of channels are of the same chirality. The distance between the centers of the two different channels is ~1.5 nm. This distance is sufficiently close to allow energy transfer via nonradiative dipole-dipole coupling between arrays of different dyes included in these channels as shown in this study. The trigonal and hexagonal onedimensional channels have diameters of 1 nm and 0.7 nm, respectively. The larger channels have the aromatic rings of the ligand positioned in parallel to the channel's orientation, opening up the possibility of ππ interactions with guest molecules. The diameters of the two channels are sufficiently large to allow small dyes such as sodium resorufin to enter, as recently shown by us for isostructural crystals . We hypothesized here that although the difference in the diameters of the two channels is only ~0.3 nm, it could be possible to selectively functionalize these channels with different dyes based on their dimensions. Relatively small dyes would enter both channels, whereas the larger dyes can only enter the trigonal channels.