It is known that biological tissues often possess a high level of heterogeneity concerning chemical composition and morphology, which is essential for the tissues to function properly. Importantly, pathologies are often linked with a change in its chemical composition and 3D morphology. Therefore, it is necessary to achieve an in-depth understanding of the full 3D structure of these tissues. Certain contrast-enhancing staining agents already exist on the market, which attach to a specific region within the tissue or type of tissue. As the binding mechanisms and mode of action of these agents is not wellknown, specific binding cannot yet be insured. The general aim of this PhD project is the synthesis of novel, target-selective contrast-enhancing staining agents (CESAs) for contrast-enhanced XCT (CE-CT) imaging. Multiple approaches will be used in the synthesis of these CESAs. Existing CT contrast agents and histological stains will be modified and novel CESAs will be synthesized based on medicinal relevant multicomponent reactions.