Light addressable machinery translation to lipid membrane structures is highly desirable for a variety of uses such as liposome drug or imaging agent delivery, membrane-bound photosynthesis analogues, etc., but little is known in this area. This thesis focuses on two objectives: the translation of triplet-triplet annihilation upconversion (TTA-UC) to liposomal systems and the use of MSLBs as tools to interrogate the behaviour of photosensitizers in these systems using surface sensitive methods. TTA-UC produces high-energy photon from low- energy excitation via Dexter energy transfer mechanism between photosensitizer and annihilator. TTA-UC uses low-power non-coherent light sources to produce anti-Stokes emission. It thus holds significant potential for photoactivated drug delivery and biological imaging since it can be stimulated using low-frequency light that penetrates biological tissue. Incorporating molecular elements into liposomes and TTA-UC in cell membranes can help biological applications and treatment without harming other organs. However, TTA-UC in a liposome or cell membrane is difficult and requires appropriate photosensitizer and annihilator that can be co-confined to the membrane and where their collisional energy transfer is supported. This thesis explores TTA-UC in solution and lipid bilayer membrane using BODIPY- and Ru(II) complex-based photosensitizers. Using new BODIPY-perylene-based photosensitizers, heavy atom effects that increase intersystem crossing via spin-orbit coupling and other heavy atom-free photosensitizers that support triplet state formatting for efficient TTA-UC are investigated. TTA-UC efficacy in cell membrane models is assessed by incorporating the molecules into liposomes, which emit intense oxygen sensitive blue/violet emission upon green excitation. The liposome-based TTA-UC further expanded into various membrane compositions with varying membrane’s physicochemical properties to simulate the effects of viscosity/fluidity on TTA-UC. TTA-UC’s response to enzyme-catalysed membrane hydrolysis was examined. A thorough study using MSLB provides insights into the photosensitizer's lateral diffusion and membrane fluidity. MSLB's versatility is assessed for comprehending membrane fluidity responses to drugs and photosensitizers.