ABSTRACT This paper presents a first approximation of the relationships within and between complex prepositions and complex subordinators from a cognitive vantage point. Because of the similarities between the two categories at the syntactic and functional levels of analysis, we first hypothesize the existence of a common productive schema that encompasses members of both classes within the framework of Construction Grammar. We then put forward a methodology developed in Diachronic Construction Grammar to analyze the within- and between-category constructional links in complex prepositions and complex subordinators in American English. We use multivariate quantitative methods to highlight the similarities and dissimilarities between the categories and make them visually identifiable. The application of this methodology to historical corpus data reveals that contrary to our expectations, complex prepositions form a relatively stable schema over time, without converging towards a common schema with the loosely connected complex subordinators under scrutiny.