Innovation is very important in current times. It is a major weapon that enhances competitive advantages. Four types of innovations are reported in literature: continuous improvement, modular innovation, architectural innovation and radical innovation. In this paper we give theoretical framework that relates modular (MI) and architectural innovations (AI) to different organizational variables. Contribution of authors on modular and architectural innovation is scattered. Here we put all these in one place. In this paper we present eighty nine theoretical propositions.