A major research challenge in the architectural design of a software-intensive System-of-Systems (SoS) is to enable the formal modeling of its evolutionary architecture. One of the main issues is that SoS architectures evolve dynamically, during run-time, in unexpected ways while producing emergent behaviour. To address this issue, this paper proposes a novel process calculus, called π-Calculus for SoS, defined as a novel variant of the π-Calculus based on concurrent constraints and inferred channel bindings for enabling the formal modeling of software-intensive SoSs, meeting their challenging architectural characteristics.