There are benefits and risks involved in interactions between public research organisations (PRO) and the productive sector. The better the balance between them the larger the knowledge value of linking. This paper proposes a conceptual framework that associates actors’ motivations for linking and modes of interaction. It suggests that under specific conditions related to knowledge capabilities and behaviour some modes of interactions have better knowledge value and thus should be promoted against others. The main claim is that bi-directional modes of interactions (i.e. knowledge flowing from PRO to firms and viceversa) optimise the knowledge value of linking conditioned to both actors having high knowledge capabilities and behaving proactively. Using propensity score matching techniques with original data for linked firms, the paper found that those conditions were met for firms forming bi-directional linkages with PRO in Argentina.