Mesopotamia and the pastoral-based, hierarchical communities of the Eurasian steppes. Renowned for its wealth in natural resources, it has recently been envisaged as a potential bridge transmitting goods and knowledge between Eurasia and the Near East. This paper summarizes the cultural evolution of the South Caucasus between ca. 6200 and 3500 BCE with a view towards emphasizing its geo-strategic position during the Late Chalcolithic period (ca. 4500–3500 BCE). From a secluded region bypassed by major circulation routes during the Neolithic, the South Caucasus evolved into a kind of economic hub, as shown by a remarkable increase in the number of settlements belonging to the Chalcolithic, many of which display evident links with Mesopotamia, Iran or the Black Sea region. This striking evolution probably stems from the rise of extractive metallurgy, which developed in the Caucasus some time during the 5th millennium BCE. Drawing on the evidence that has been collected in Nakhchivan over the past 15 years, in particular on the obsidian circulation networks, we argue that the exchange of goods and knowledge during the Chalcolithic was in the hands of mobile pastoral groups, which resulted into a chain of interconnected networks of varying extents. According to this scenario, the circulation units at the beginning of the larger, interregional networks did not necessarily have any contact with the end-line. From the available evidence, the South Caucasus during the Late Chalcolithic appears to have been a kind of hub, a central place where different communities met and interacted: this is particularly visible in Nakhchivan, where mobile herders from Iran, among other groups, established links between the communities living in Eastern Anatolia and those of the Lesser Caucasus piedmonts.