Aim The presentation traces the emerging roles of institutional repositories in Serbia, beyond the main task required by the national Open Science (OS) policy (adopted in 2018): to serve as Green Open Access (OA) venues. Background At the time when the national OS policy was adopted (2018), Serbia had already had a developed network of Diamond OA journals and a national repository of PhD theses, but there were only a few fully functional institutional repositories. To comply with the policy, which mandates Open Access to publications, research organizations have undertaken to establish institutional repositories, without dedicated financial support from public funders. Almost three years later, there are around 40 repositories and their content goes beyond the policy requirements. Methods The presence of content types not covered by the OA mandate (posters, images, research data, etc.) and the coverage of content from the period preceding the adoption of the OA mandate are taken as the quantitative indicators of the emerging roles for institutional repositories in Serbia. We analyze content types in around 40 institutional repositories based on data provided by repositories and aggregators. A qualitative analysis based on a survey conducted among repository managers is also presented. Finally, as the authors are also members of a repository development team, a brief overview of measures taken towards supporting the emerging roles of institutional repositories is given. Results and discussion The results show that although most institutional repositories in Serbia were established with the aim of ensuring compliance with the OA mandate, research organizations have assigned them other roles, namely: to serve as comprehensive digital libraries of the institution’s research outputs as, far back in history as possible, no matter whether the content is OA or not; to serve as a source of information in various reporting procedures (annual reports, promotion procedures, etc.); to showcase the institution’s publishing activity; to make print-only publications, especially monographs, available in a digital environment; to showcase various non-publication outputs (technical reports, posters, promotional materials, students’ works, etc.) to serve as research data repositories. One of the most important incentives for this is the high visibility of local repositories and their content in international aggregators, discovery platforms (OpenAIRE, BASE, CORE), and search engines (Google Scholar). There is an apparent tendency to make content open whenever possible. Interestingly, institutional repositories in Serbia are still not used for sharing Open Education Resources and training materials. The initiative to increase content diversity in an institutional repository usually comes either from institutional decision-makers or from librarians. Whether an innovative idea in this direction will be realized or not largely depends on the readiness of repository development teams and librarians to support it. Conclusion In most cases, once an institution decides to invest in a repository, it wants to make the best use of it, especially if its functionalities can make up for some missing links in the local infrastructure for scholarly communication (e.g. book publishing platforms or CRIS). Our analysis shows that institutional repositories can successfully meet various innovative needs and serve as crucial building blocks of open scholarly communication if appropriate support from repository developers and librarians is provided. Furthermore, training related to repositories and researchers’ involvement with this type of infrastructure contribute to the development of skills relevant for Open Science and scholarly communication. The fact that innovative initiatives come from within institutions, without any pressure from research funders, indicates that there is an intrinsic interest in open scholarly communication. On the other hand, the lack of incentives from the responsible ministry may be discouraging in the long term.