This thesis is entitled 'Molecular Logic Gates Bound To Solids' and is separated into five chapters. The first chapter introduces logic gates and the potential applications of molecular logic gates. Photochemical mechanisms, Photoinduced electron transfer (pET) and Internal charge transfer (lCT), through which many sensors and molecular logic gates operate are focused upon. It also reveals how the application of chemical or optical inputs and optical outputs from molecules, with the aid ofthe PET and ICT mechanisms can construct molecular logic gates. Chapter 2 presents molecular logic gates which are prefabricated and covalently bound onto organic and inorganic beads. The YES and PASS 1 operations are displayed both individually and in parallel and are driven by proton inputs. Chapter 3 entails the introduction ofternary logic with the 'off-on-off' logic gate. Its . operation in solution is transcended when covalently attached onto a solid platform and is driven by proton inputs. Chapter 4 involves the discussion of double-input logic gates. The AND gate which is solid-bound is driven by protori and sodium ion inputs. Chapter 5 demonstrates how selectivity· of logic gates govern their operation. The YES and OR molecular logic gates are performed on the organic and inorganic beads through calcium and zinc ions. Chapter 6 presents analytical data and experimental procedures for all molecules included in Chapters 2, 3, 4 and 5. IV