In literature, positive contributions of Information and Communication Technology (ICT) to productivity has been found; It is also found that the ICT-using industries benefited most, provided that complementary organizational investment has been carried out in firms. However, the mechanisms at micro level behind this positive link between ICT and productivity in ICT-using industries, as well as those behind the link between the complementary organizational investment and productivity, are not clear. These questions motivate the following studies. The literature review identifies two major dimensions of ICT impacts on the core activities of the firm. They are (1) the communication and processing of information; and (2) the accumulation and distribution of organizational knowledge. Under the two dimensions, ICT enhances the firm’s abilities to create higher value-added in products and services, and thus to improve productivity. Therefore, the firm activities are the keys in turning the advantages of ICT into higher productivity. The following studies contribute present specific models under the two dimensions. For the first dimension, a model is presented with the firm assumed as an information-processing organization, which is an alternative to markets in coordinating production in markets with demand uncertainty.