To examine the pillar-induced changes in crystal structure, powder X-ray diffraction (XRD) patterns of the pristine HTO and the molecularly pillared HTO-PA and HTO-HDA are shown in Fig. . The XRD pattern of as-synthesized HTO is in close agreement with that reported in literature (PDF 00-036-0655), which indicates the successful synthesis of the protonated/hydrated phase from the precursor K2Ti4O9. ICP results (Table ) show that only negligible amounts of potassium remain in the structure (ca. 0.2 wt.%), indicating successful ion exchange by acid treatment. Upon the introduction of the molecular pillars, both HTO-PA and HTO-HDA exhibit a strong shift of the peak of the (200) set of planes to lower angles, indicative of an increase in the interlayer spacing from 0.88 nm in the pristine HTO to 1.58 nm in both HTO-PA and HTO-HDA. The similar interlayer spacing and morphology of the two molecularly pillared titanates, HTO-PA and HTO-HDA, permits to exclusively assess the impact of cross-linking versus layer-separating/non-cross-linking molecular pillars on the electrochemical properties.