This study examined the expressive and perceptual functions of eyeblinks and their synchronization during real-time mutual gaze interactions, aiming to elucidate their role in nonverbal communication dynamics. Using dual eye-tracking, we recorded the gaze behavior of 50 participants (25 dyads) engaged in a novel asymmetrical dyadic task designed to isolate gaze-based interactions without verbal cues. In this task, one participant (the listener) was presented with emotion-inducing auditory stimuli and instructed to experience the emotions elicited by them, whereas the other (the observer) attempted to infer the listener’s emotional state solely through gaze without hearing the audio stimuli. Blink behavior was analyzed across three consecutive segments: baseline, audio, and silent. Results revealed contrasting effects of the auditory stimuli on blink frequency: in the audio segment, listeners blinked more frequently, while observers blinked less, reflecting task engagement and attentional roles. Furthermore, blink synchronization was significantly reduced during audio segments compared to baseline, suggesting task-driven disruption in shared gaze dynamics. These findings highlight the role of asymmetrical tasks in shaping blink dynamics and interpersonal alignment of blinks. Notably, observers perceived and adapted to changes in the listeners’ blink patterns, even without awareness of the transition between segments, underscoring the subtle mechanisms of nonverbal feedback. Taken together, by demonstrating the interplay between task structure and blink dynamics, this study illuminates the expressive and perceptual potential of blinks, contributing to a deeper understanding of gaze-based communication in dyadic social interactions.