This article presents the initial results of the project The Building Blocks of Croatian Mental Grammar: Constraints of Information Structure, within the scope of which the Croatian Psycholinguistic Database is being constructed. The database contains empirically established values for the categories of concreteness, imageability, subjective frequency and age of acquisition for 3000 lexemes (nouns, verbs and adjectives) of Croatian extracted from the hrLex lexicon whose frequency was extracted from the hrWaC corpus. The article starts with an overview of research dealing with concreteness and imageability, followed by a presentation of the methodology employed in the construction of the Croatian Psycholinguistic Database. The central section of the article presents the statistics concerning concreteness and imageability estimates for the sample taken in its entirety, as well as divided according to lexical class. The results show that both concreteness and imageability differ according to lexical class. These results are discussed from the perspective of constructional cognitive linguistic theories.