We present a critical reexamination of individual electronic and collective optical nonlinearities of nematic liquid crystals (NLC) in the context of all-optical transmission switching of femtoseconds - CW lasers, and report recent observations of similar optical nonlinearities in Blue-phase liquid crystals (BPLC) and their utilization in feasibility demonstrations of polarization-free nonlinear grating diffraction and transmission switching of CW as well as pulsed lasers.