This chapter explores the potential of chatbot-based coaching to foster meaningful relationships between coach and coachee. Drawing on an interdisciplinary research project at the intersection of human–machine interaction and coaching effectiveness research, it investigates what conversational strategies help establish a trustful relationship—defined through rapport, working alliance, and social presence—between humans and machines. Through a design-based research approach, key relational elements such as coachbot self-disclosure, empathic feedback, and generative AI’s paraphrasing capabilities were found to enhance users’ perception of social presence and strengthen the working alliance. Practical recommendations address both structural and linguistic dimensions of coaching chatbot interaction, while also underscoring ethical considerations and design implications for generative AI. The findings offer guidance for the responsible integration of AI in coaching contexts. The chapter concludes with future-oriented theses on the role of AI-based chatbots in coaching and highlights emerging research avenues.