As a self-organizing macromolecule, hydroxypropylcellulose serves as an excellent candidate for studies of complex polymer mixtures. In this work, we examine aqueous mixtures composed of two hydroxypropylcellulose grades, Klucel-F (HPC) and Klucel-H (HHPC), with molecular weights of 10 5 and 10 6 g mol - 1, respectively. Polarized light microscopy and deuterium nuclear magnetic resonance have been utilized to ascertain changes in the chiral nematic mesophase of HPC upon addition of 15 wt% HHPC. Results obtained here suggest that the HHPC either disrupts the molecular organization of the HPC mesophase, or induces immiscibility and partitions between HPC- and HHPC-rich phases.