Abstract. Multimodal and dialogue-based mobile interfaces to the Semantic Web offer access to complex knowledge and information structures. We explore more fine-grained co-ordination of multimodal presentations in mobile environments by graph visualisations and navigation in ontological RDF result structures and multimedia archives. Semantic Navigation employs integrated ontology structures and leverages graphical user interface activity for dialogical interaction on mobile devices. Hence information visualisation benefits from the Semantic Web. Constraint-based programming helps to find optimised multimedia graph visualisations. We report on the constraint-formulisation process to optimise the visualisation of semantic-based information on small devices and its integration in a distributed dialogue system.