Abstract: The invention relates to a method for the preparation of micro- or nano crystalline cellulosic compositions from virgin cellulose containing amorphous and crystalline cellulose phases comprising the following steps: (A) contacting virgin cellulose with a first solvent, characterized in that the first solvent is an aqueous solution comprising 40-65 wt. % ZnCl2 in water, relative to the total weight of the of ZnCl2 and water, (B) dissolving the amorphous cellulosic phase, whereby the amorphous cellulosic phase is preferentially dissolved over the crystalline cellulosic phase, (C) separating the dissolved amorphous cellulose from the crystalline cellulose and preferably step C wherein the obtained micro- or nanocellulose has XRD type I structure, which then can be contacted with a second solvent comprising between 65 and 90 wt. % ZnCl2 in water to produce delaminated cellulose having XRD type II structure.