The obtained trigonal lattices are closed-packed (Figure ). In contrast, P212121 structures are not closely packed due to their symmetry. However, their 2D arrays resemble a closepacked structure (Figure ). In fact, their packing densities are nearly identical to those of the corresponding trigonal lattices [e.g., the densities of (M)SubPc-3Cl(α) and rSubPc-3Cl(α) crystals are 1.624 and 1.645 g cm , respectively, Table ]. Hence, we consider that, in this system, P212121 is a kind of closed-packing for antiparallel arrays of 1D columns.