The use of information and communication technologies to improve environmental sustainability has become a new focus of the IS research in the last years. Different Green IS solutions in various areas already exist, that contribute to the environmental, economic or social performance of organizations. Although these solutions are more and more used within companies, the adoption rate of these solutions varies. This paper focuses on the reasons for these differences by using the Diffusion of Innovation theory as a basis for an exploratory study. In a first step Green IS solutions that are currently available on the market are identified. Based on these alternatives, a survey among Austrian enterprises to analyze how the perceived complexity of the solutions influences their diffusion was conducted. The respondents had to classify the complexity of the respective Green IS solution and specify the realization in their company. Results showed that Green IS solutions and measures that are seen as simple in their technical complexity are adopted more frequently.