Abstract:The successful growth of Bi 2 S 3 nanocrystals in glass matrix using SiO 2 (Silicon Dioxide), K 2 O (Potassium Oxide), Na 2 O (Sodium Oxide), B 2 O 3 (Boron Trioxide), ZnO (Zinc Oxide) and TiO 2 (Titanium Dioxide) as key components is done using the fusion method. Different sizes of nanocrystals in glass matrix were grown by annealing the glass (dispersed with Bi 2 S 3 nucleons) under two different conditions. The glass was annealed between 6 and 48 hrs at constant temperature of 550 o C. The glass was also annealed at the temperature between 550, 575 and 600 o C at constant annealing time 6 hrs. The photocatalytic H 2 generation under solar light has been performed and utmost H 2 generation i.e. 5545 µmole h -1 g -1 has been achieved, which is higher than Bi 2 S 3 powder The Bi 2 S 3 nanocomposite obtained was characterized by Optical Transmission (OT) spectroscopy and Transmission Electron Microscopy (TEM). Optical Transmission (OT) spectroscopy revealed strong red shift in transmission cut off which indicates increase in particle size of nanocrystals under both the conditions. TEM analysis demonstrated the nanocrystal size in the range of 3 to 12 nm.