Akan, like any other language, has both regular and irregular complex nominals (CNs). However, previous studies of Akan nominals have been constructive in approach, mostly adhering to a strict form of the principle of compositionality and assuming that the morphological, phonological and semantic properties of CNs can be accounted for fully by tweaking those of their constituents. Consequently, CNs whose properties cannot be so accounted for are either ignored or forced into the mould of regular ones. In this study, I do three things. First, I present a detailed empirically-based assessment of attested CNs in Akan based on a dataset of 1000 CNs drawn from a variety of written sources. This shows that Akan CNs may be grouped into four; compounds, affix-derived CNs, those formed by tonal changes and “lexicalized” forms, which have the form of phrases but occur as CNs and are mostly only partially compositional. Secondly, I present a detailed discussion of the formal and semantic properties of all the attested compounds and a subset of the lexicalized nominals. Thirdly, on the basis of the latter discussion, I examine what the formation and structure of CNs reveal about the interaction between morphology and syntax and about the architecture of the grammar. The analyses show that the formation of CNs in Akan may at once involve morphological and syntactic structure in a way that renders untenable the view that morphology and syntax constitute two completely different modules of the grammar which may be assumed to interact only because the output of the former is the input to the latter. The present study provides support for the constructional view of the grammar.