A major goal in the study of the interface between syntax and morphology (understood as part of the PF component) is to understand mismatches between syntactic representations and the corresponding morphological representations. Denominal adjectives in Bulgarian provide one such mismatch. In morphology, they are composed of a nominal component D adjoined to an adjectivizing head F. In syntax, however, the nominal component D behaves like a nominal phrase occupying the specifier of F. Denominal adjectives in Bulgarian thus present both a structural mismatch whereby a syntactic specifier-head relation is mapped to head adjunction at PF and a mismatch between the syntactic and morphological category of denominal adjectives. I analyze these mismatches as the result of a morphological (postsyntactic) operation, which converts nominal phrases into denominal adjectives postsyntactically, as part of the word formation process that combines the nominal phrases with adjectivizing morphology. The proposal is an extension of the theory of the syntax-morphology mapping developed within Distributed Morphology (Embick and Noyer 2001, et seq.) on the basis of Marantz’s (1984) Morphological Merger and relies on the implementation of Morphological Merger developed by Harizanov (2014a) in the context of cliticization, itself an elaboration of Matushansky’s (2006) and Nevins’s (2011) proposals.