The Internet of Things and the amplified capabilities of smart products can be increasingly utilised for the development of feedback-rich systems and loops throughout the entire product life cycle. By adopting the IoT and collecting data during product utilisation, companies can replace the end-of-life concept with product life extension and circular loops. In this sense, service business models hold the greatest potential to optimise the utilisation of goods over time. These models allow a reduction of the overall life cycle costs and contribute to resource-efficiency and the transition towards a circular economy. This paper introduces the concept of smart-circular systems that reflects the interplay between the Internet of Things, the circular economy and service business models and presents a conceptual framework for further empirical analysis of this phenomenon. The framework focuses on product-service systems and more broadly on services business models that optimise the utilisation of goods over time through the amplification of circular activities by the introduction of smart enablers. It also considers three main business models types and tactics for successful implementation of service business models.