The thermally stimulated currents (TSCs) technique were applied to investigate layered organic photoconductors (OPCs) based on azo pigments and hydrazone compounds. The amount of collected carriers was measured with TSC and discussed in terms of carrier generation mechanism. Temperature and/or electric field dependence of generation, recombination and separation processes of ion-pairs were analyzed by using the layered organic photoconductors using the symmetrical and unsymmetrical azo pigments and hydrazones. The sensitivity of OPC sample was mainly determined by the process of initial ion-pair (or charge transfer state) formation. The difference caused by materials is discussed.