This paper describes the design and implementation of a Unicode-based GUISL (Graphical User Interface for Sindhi Language). The idea is to provide a software platform to the people of Sindh as well as Sindhi diasporas living across the globe to make use of computing for basic tasks such as editing, composition, formatting, and printing of documents in Sindhi by using GUISL. The implementation of the GUISL has been done in the Java technology to make the system platform independent. The paper describes several design issues of Sindhi GUI in the context of existing software tools and technologies and explains how mapping and concatenation techniques have been employed to achieve the cursive shape of Sindhi script.