The formation of Cu3(HHTP)2 with each modulator was confirmed by powder X-ray diffraction (PXRD) (Fig. ). The PXRD patterns of ammonia, DMF and pyridine-modulated Cu3(HHTP)2 (A-CuHHTP, B-CuHHTP, and C-CuHHTP, respectively) each displayed intense diffraction peaks in the lower 2θ region, indicative of relatively high crystallinity of the as-prepared frameworks. However, the XRD patterns hinted at potential differences in the stacking sequences of the two-dimensional sheets between the three samples. The patterns from A-CuHHTP and C-CuHHTP showed relatively good agreement with simulated XRD patterns of Cu3(HHTP)2 subunits with both the P6/mmm space group, with eclipsed cofacial AA-stacking of the layers, and the C2/m space group, with near-eclipsed staggered AA-stacking (i.e., a constant stacking shift of the sheets) (Fig. ; SI Table ).