We investigated the electro-optic properties of nematic liquid crystal cells oriented by polyimide (PI) layer doped with 3.5 nm semiconductor quantum dots (QDs) CdSe/ZnS at concentrations of 0.05 and 0.1 wt. %. It is shown that doping PI orienting layer by QDs reduces the permittivity and the phase delay, as well as increases the electrical resistance of the cells. Also we observed deceleration of liquid crystal (LC) optical response caused by the screening effect of the orienting layer