The use of a variety of green solvents to swell a diverse range of resins used in solid-phase synthesis is investigated. Good swelling is shown to depend on the structure of the resin and the solvent. A modelling approach based on use of a training set of solvents is used to predict which green solvents will, and will not, swell a particular resin. The chemical relevance of the swelling results is confirmed by an experimental study of a solid-supported Ugi reaction carried out in green solvents.