Architecture today faces urgent demands for sustainable transformation in the context of climate change and ecological crisis. A central challenge lies not only in improving material performance or reducing emissions, but in rethinking how materials shape architectural thought, form, experience and perception. Traditionally, architectural materiality has been approached either through technical-environmental metrics or through socio-symbolic interpretation—rarely through an integrative lens. Here, we propose that Material Engagement Theory offers a productive conceptual framework to bridge this divide by understanding materials not as passive matter but as active participants in cognition and cultural expression. Through comparative case studies of “openness” (window typologies in East Asian tradition and the European classical tradition) and “mass” (uses of clay across climates and cultures), we demonstrate that seemingly simple material choices reflect deep epistemologies and embodied practices. Paper and glass windows, for instance, reveal distinct cultural engagements with light and vision, while clay construction—from rammed earth and adobe to brick domes and timber-frame infill—manifests diverse tectonic logics of embodied mass. These findings suggest that a meaningful paradigm shift toward sustainability in architecture requires not only technological innovation, but a deeper cognitive-material reorientation in how we design with and through materials. This study contributes to emerging conversations on the conceptual foundations necessary for such a shift in architectural thinking and practice.