Abstract. We report on the notation and tool integration framework developed in the application-oriented research project Espress. The framework is based on a Z core and provides means of integrating formalisms on a syntactical, semantical as well as tool technical level. Currently, the framework integrates Z with the languages of Statemate 15], i.e. Statecharts to describe reactive behavior and activity charts to describe structural aspects. Our means of integration are, however, general enough to integrate other, esp. synchronous languages, as well, and reuse much of the existing tools in the process.