Designers will always face the challenge of designing well-performing buildings using what are often conflicting and competing performance objectives. This thesis presents a workflow called the ‘creative optimization workflow’ using a Multi-Objective Optimization (MOO) engine called Octopus that runs within Grasshopper3D, a parametric modeling tool, and multiple simulation software. Developed as part of the workflow, the ‘creative optimization tools’ make MOO based solutions more accessible to the designer and enables the exploration and analysis of the solutions from a visual and analytical point of view. Through the juxtaposition of extreme performing solutions, serendipity is created and the potential for better multiple performing solutions is increased. The application of the workflow on the retrospective design of two buildings, De Rotterdam and the Bow Tower, is presented. The developed workflow and tools help to reduce design latency through automated generation of design solutions, incorporate disparate performance domains including formal aesthetics and explore trade-offs of multiple solutions all within one platform.