If the formalization of space and time in regional economic models has gone through decisive improvements, what has always been, and still is, a difficult step forward in the conceptualization of a modern regional science is the convergence between the formalized, analytical approaches with the qualitative, conceptual ones that have enriched regional economics since the 1970s, moving the main focus of analysis from “space” to “territory”. Within the general goal of moving towards a convergence between formalized and qualitative approaches, the paper presents the view and the research style in regional science that characterized the long lasting years of cooperation of two authors, always in search for conceptual tools able to interpret the complex reality at best. In particular, authors are convinced that evolutionary approaches are necessary for the interpretation of complex regional as well as urban economic systems. The authors developed new theoretical views characterized by an evolutionary approach and by sound empirical evidence. Moreover, the two authors are convinced that long run competitiveness is a supply side phenomenon, based on tangible and intangible assets indicated along sixty years of regional science theorisation. All these elements have been synthetized in the concept of territorial capital, and have called for a complementary and synergic use of its different assets and their balanced development. All these convictions led the two authors to the idea that a modern approach to regional growth calls for the implementation of regional growth theories based on a relational-stylised space, through an integration between national, macroeconomic processes and territorial assets and specificities, something that has hardly been taken into consideration in regional science up to now. The paper presents a first formalized model of this kind.