Complexity science offers a powerful perspective for studying process theory in Information Systems (IS). Process theory explores how events, actions, and interactions evolve over time. Although complexity science is well-established in other fields, its use in IS research remains limited. In this study, we apply complexity-based methods, particularly mathematical modelling, to deepen our understanding of IS processes. We focus on business-IT alignment as a case example. By building and analysing a dynamic model, we show that alignment follows complex, nonlinear patterns, such as feedback loops, tipping points, and oscillations, that traditional research methods often miss. Our findings highlight how system dynamics and complexity science can reveal hidden structures in IS processes and provide new tools for researchers.