PurposeThe subject of this paper is the phenomenon of social media aesthetics, which can be perceived as a tool for promoting and building the image of libraries, especially in terms of merchandising. The aim of this paper is to analyse the potential of the dark academia social media trend in the promotion of academic libraries.Design/methodology/approachThe article is based on a review of the social networking sites YouTube and Instagram and an analysis of network resources using the Brand24 tool.FindingsResources that are described by Internet users as “dark academia” are popular in social media. Dark academia as an aesthetic concept creates potential for the promotion of academic libraries, especially those that are more traditional in terms of their architecture, décor or how they offer their services.Research limitations/implicationsThe paper concerns a phenomenon which, although popular socially, has not yet been scientifically analysed in the literature on the subject. Since the topic is new and there is no scientific literature on it, the author had to base the paper on less standard sources of information (e.g. analysis of the content of social media). The article is a review, an introduction, as well as an invitation to further discussion. The author's aim is not to comprehensively cover this topic but only to draw attention to an interesting and rarely discussed issue that has great potential for practical activities.Practical implicationsThe topic has great potential for the practical improvement of the promotional activities of libraries, especially older, more traditional libraries, to create a strong and positive image on the basis of characteristics often perceived as weaknesses.Social implicationsSocial media services are powerful social impact tools. Showing the potential role of social media aesthetics for cultural institutions could serve to make the public more aware of the role of the proper use of social media for promotion and image building.Originality/valueThe use of social media aesthetics is very rarely discussed in the subject literature.