Bioimaging, essential for visualizing biological structures and processes, encompasses diverse modalities such as MRIMagnetic Resonance Imaging (MRI), CT, PET, and optical imaging. Recent progress integrates stimuli-responsive nanomaterials, offering targeted imaging with improved contrast and specificity. This chapter explores how nanomaterials can change in response to factors like pH, temperature, and light, improving imaging quality. It covers how these nanomaterials are made and how they work, focusing on their use in optical, ultrasound, X-ray, and MRI imaging. Furthermore, it discusses multimodal imaging strategies, showcasing the potential of stimuli-responsive nanomaterials to revolutionize diagnostic and therapeutic approaches in medicine. Ongoing research promises continued refinement and expansion of these technologies, marking a transformative era in bioimaging.