Aurivillius compound SrBi2Ta2O9 (SBT) is a futuristic material with applications mainly in ferroelectric memory devices. This is due to their excellent fatigue resistance and other electrical properties. Most importantly all the constituents of parent material and/or by modifications as a whole are environmentally safe. Here we presented the various physical properties such as structural surface morphology electrical and photocatalytic analysis of SBT and its substitutions (Ce4+ Dy3+ and Y3+). Substitutions at A-site and Bi-layer effectively modifies the electrical properties as well as photocatalytic analysis. Trivalent elemental substitutions at A-site induce cation vacancies to satisfy the charge neutrality which significantly improves the ferroelectric property. The various functions are used to analyze the electrical parameters. Finally the photogenerated electrons and holes are separated spontaneously by ferroelectric domains to enhance the H2/O2 evolution. For a better understanding of ferroelectric as a photocatalyst the relation between electrical and photocatalytic properties are correlated.