Past research has demonstrated the validity of co-evolutionary model in depicting human design activities, while few empirical studies have articulated the connections between design behavior and implicit cognitive process during team-level design co-evolution. This paper proposes a novel method that incorporate a neurobiological indicator, inter-brain synchrony (IBS), to measure brain behaviors and neural connectivity among interacting collaborators. We documented participants’ verbal and behavioral data via video recordings, as well as simultaneously captured their neural responses utilizing functional near-infrared spectroscopy (fNIRS) while they were engaged in a conceptual design task. These codlings were adopted to segment the recorded protocol data into smaller episodes, serving as the basis for the subsequent fNIRS data analysis. Preliminary findings revealed the effects of exploring dimensions (problem and solution) and communication approaches on neural synchrony among collaborators.