Mobilising knowledge from healthcare research into practice remains a global challenge. Alongside increasing recognition of the importance of knowledge mobilisation, academics are expected to have, and to demonstrate, impact from their work. One way in which they attempt to do so is to develop outputs, in addition to journal papers, such as toolkits and dashboards, which are defined here as products from healthcare research. Products from healthcare research may be developed with the aim of helping practitioners to mobilise research findings into practice. Despite their increasing ubiquity, the development of such products remains understudied, highlighting a gap in current understandings. This research contributes to addressing this gap, using boundary object theory as a lens through which to analyse the development of products from healthcare research. Boundary objects may be viewed as helping transform knowledge between different communities of practice. This research conceptualises products from healthcare research as designated boundary objects, and develops understanding of how they might emerge from their designated state into boundary objects-in-use. Drawing upon qualitative data generated from an exploratory study (20 semi-structured interviews and a focus group (n=11)) and four prospective, longitudinal case studies of research projects which aimed to develop products from healthcare research (38 semi-structured interviews, 83 hours of observation, analysis of ~300 documents), it addresses the research question How does the development of products from healthcare research influence their emergence as boundary objects-in-use? This research identifies that products from healthcare research may be developed because academics expect them to help mobilise research findings into practice. They may also be proposed in response to the 'impact agenda', and for symbolic purposes to try to secure grant funding in response to the perceived desires of funders. Three interconnected aspects may be necessary (but not sufficient) for designated boundary objects such as products from healthcare research to emerge as boundary objects-in-use. These aspects are: a perceived need for the product; clear end-users; and clear aims. The emergence of products as boundary objects-in-use is dependent upon an implicit understanding of end-users' needs. This understanding may be gained either by individuals with implicit understanding playing a key role in product development, or through engagement with end-users. Dissemination of the product may also contribute to the emergence of a boundary object-in-use. Plans for stakeholder engagement, dissemination and evaluation relating to product development within funding bids may be proposed for symbolic reasons to help secure their success. The high (and increasing) pressures upon academics to achieve certain research metrics, conceptualised here as the 'academic treadmill', in addition to the short term-ism generated by time-bound academic projects, make it difficult for them to meet the (over) ambitious targets laid out in research proposals. Existing accounts of boundary object theory propose that a new joint field needs to form between developers and end-users during use of the object in order for it to emerge as a boundary object-in-use, and assume that boundary objects will only be used if end-users have direct contact with boundary spanners in practice (people who successfully span boundaries). This research shows that end-users may use boundary objects even when they do not have direct contact with boundary spanners in practice, and contributes to boundary object theory by drawing on the empirical data to propose that where the boundary object in question is used at a distance from its developers (akin to a hand-over), the emergence of a boundary object-in-use requires the formation of a new joint field during its development rather than a new joint field of use. This research suggests that developing fewer, high quality products, which meet a need and summarise cumulative evidence, helping practitioners to improve care quality, is an ambition worth striving for.