Hybrid materials based on water soluble polymers : preparation and application in sensing and photocatalysis This thesis describes the strategies for the innovative design of polymeric organic inorganic hybrid materials using the development of synthetic approaches. The key objective of reported designs here is the excellent engineering of organic and inorganic building units that can successfully organize into target architecture of hybrid materials with ordered structures. Hereby this thesis explains the strategies and corresponding their methods and results within three main chapters which cover (i): the synthesis of (co)polymer and semiconductor metal nanoparticles (NP) (ii): solution behavior and crystallization driven self assembly of hybrid materials and (iii): the application of the obtained organic inorganic hybrid materials in photocatalysis and the sensing of heavy metal ions. In the first part of this thesis we describe the synthesis of mostly double hydrophilic graft and block (co)polymers to be used as templates and to form the shell in hybrid materials such as noble metals or CdS NP and core shell hybrid materials like polymer@SiO2 and TiO2 nanoparticles. The second part focuses on the self assembly of (co)polymers and hybrid materials using the crystallization driven self assembly (CDSA) approach. The last part is focusing on exploring the performance of copolymer containing hybrid materials in various applications. To cut a long story short this thesis describes straight forward methods to tailor organic inorganic hybrid materials to create appropriate and unprecedented hierarchical superstructures or hybrid materials for a variety of applications including directional self assembly metal sensors water splitting and immobilization of organic and inorganic nanomaterials.