The information systems (IS) community has developed many theories, approaches, and models that identify conditions and determinants of successful IT use. However, each model in the IS literature has evolved to address specific aspects and dimensions. This has led to conflicting results concerning the impact of IT use. Consequently, while a rich body of knowledge has emerged, with prominent models such as the Technology Acceptance Model or the IS Success Model, the complexity of defining a suitable multi-dimensional construct for IT use has largely been neglected. In this paper, we develop a new causal model of IT use. Based on Adaptive Structuration Theory, we argue for the multidimensionality of IT use and thoroughly derive its components. Moreover, we introduce two new concepts into studies of successful IT use: functional affordance and symbolic expression. Both establish a relation between the IT system under investigation and its users. In doing so, we provide a novel, synthesized approach for investigating IT use in the context of post-adoptive behaviours and the framework of Adaptive Structuration Theory.