The theory of electromagnetically induced transparency (EIT) in a nonlinear conductive medium, which utilizes the classical approach instead of the traditional quantum optics scheme, has been recently suggested. We present the results of the bichromatic parametric irradiation experiments which validate the EIT effect within the mid-infrared spectrum. The studied materials include a highly dispersive gold (Au) and a low dispersive semiconductor zinc telluride (ZnTe). When the irradiation parameters satisfy the requirements of the EIT theory, the effect was shown to be strongly pronounced in both Au and ZnTe despite the very different optical properties of these conductors. The predictions of the theory regarding the existence of the EIT effect are shown to be in agreement with the experiment.