Digital health behavior change interventions are being developed and tested at a growing pace. Indeed, digital communication technologies offer a vast array of opportunities to facilitate and support behavior change at a large scale including large uptake, constant availability and computational capabilities for data analysis. Compared to real-life personal coaches, they can be cost-effective and more scalable. However, they fail to retain engagement and show limited long-term effects due to lack of personalization of coaching interactions, an undisputed asset of real-life coaching. IMPERIO aims to develop and evaluate an effective smoking cessation program, delivered by a conversational agent or ‘chatbot’ serving as virtual coach that guides the user through a personalized & contextualized coaching program. Therefore, a strong research focus lies on the development of a trustworthy and effective virtual coach, particularly in terms of personalized conversations. Through self-learning algorithms, the chatbot coach will determine the optimal point to engage with the user. It will automatically construct personalized conversation flows to achieve the optimal coaching strategy tailored to the context, profile, personality traits, behavior & motivation of the user. Evaluation of the effectiveness of the system for smoking cessation is the final outcome.