Fundamental photophysical and photochemical processes of molecules, such as photo-absorption, emission, energy transfer, electron transfer, isomerization, photocleavage and so on, are very important in order to not only understand the nature of the molecules, but also to develop the photo-functional materials.

Over the past three decades, photochemistry of the molecules in several host materials has been developed, and this research has revealed that guest molecules show unique photochemical properties because of the distinctive medium provided by the host materials. The understanding of these unique photo-functionalities of host-guest systems will result in a contribution to the fundamental knowledge in order to design the nano-space of host materials and future applications.

Thus, this Special Issue aims to collect the recent original research and review articles related to the above area, and to collate the research with a focus on the development of other energy conversion devices utilizing hybrid systems. The main focus of this Special Issue is fundamental/advanced/theoretical research on photochemistry in host-guest systems and those applications of photo-functional devices. We also welcome the submission of research related to photochemistry on solid surfaces and the optics of host-guest materials.

Potential topics include but are not limited to the following:

• Energy conversion and synthesis utilizing host-guest system
• Fundamental/advanced/theoretical research on photochemistry and optics of host-guest materials
• Synthesis, preparation, characterization, and photo-/optical functionalities of host-guest hybrid materials.
• Photochemistry on solid surface
• Photophysicochemical processes, such as photoinduced redox reactions, photoresponses to molecular configuration (e.g., photoisomerization and photochromism), luminescence and energy transfer and linear- and nonlinear-optics in hybrid materials