The CombeChem e-Science project has demonstrated the advantages of using Semantic Web technology, in particular RDF and triplestores, to describe and link diverse and complex chemical information, covering the whole process of the generation of chemical knowledge from inception in the synthetic chemistry laboratory, through analysis of the materials made which generates physical measurements, computations based on this data to develop interpretations, and the subsequent dissemination of the knowledge gained. The project successfully adopted a strategy of capturing semantic annotations ‘at source’ and establishing schema and ontologies based closely on current operational practice in order to facilitate implementation and adoption. The resulting ‘Semantic Data Grid’ comprises around 45 million RDF triples across multiple stores.