This study investigates how connectives However and While, signaling contrast/ concession to construct stances, are distributed by AI chatbots in task-based argumentations. The corpus, comprising 13,482 words of chatbot-produced discourse, was analyzed to examine the connectives’ sentence positions and their relation to content-, writer-, and reader-oriented propositions, based on an integrated framework of Hyland’s (2005) framework and Thetela’s (1997) evaluative-entity framework. A total of 124 tokens of However and While were extracted, excluding tokens whose stance and cohesive functions can’t be clearly interpreted. Results show sentence-initial However (N=40) and sentence-initial while (N=59) are the primary devices for asserting a writer-oriented stance, signaling evaluation, claim or counter-claim. Sentence-initial while are more frequently used to frame a factual premise before projecting writer orientation. As to sentence-medial while, both preceding and subsequent clauses are often presented content-oriented propositions, indicating achieving cohesion is prioritized over expressing an evaluative stance. This study concludes that the use of these connectives, strategically applied in AI-human argumentations, shows how connectives contribute to manage stance construction and discourse coherence.