In this paper, Co-Al layered double hydroxide (LDH) and montmorillonite (MMT) have been exfoliated into charged single layers in the solvent of formamide and water, respectively. The structures of individual layers of LDH and MMT were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). The delamination mechanisms of LDH and MMT were also discussed. Furthermore, heterogeneous ultrathin films of poly(vinyl alcohol) (PVA)/charged inorganic nanosheets, (PVA/MMT/PVA/LDH)(n), were fabricated by layer-by-layer (LBL) assembly via hydrogen bonding. The LBL assembly process was monitored by UV-vis spectroscopy, and the structures of the heterogeneous ultrathin films were analyzed by XRD.