Many Organothallium Compounds have been used in medicine, industry and antibacterial activity. Optical properties are among the most fascinating and useful properties of many complexes and have been extensively studied using a variety of optical spectroscopic techniques. A basic understanding of the optical properties and related spectroscopic techniques is essential for characterization about semiconductors, insulators or metal. Optical properties are related to other properties and functionalities (e.g. electronic, magnetic, and thermal) that are of fundamental importance to many technological applications, such as energy conversion, chemical analysis, biomedicine, opto-electronics, communication, and radiation detection. The fundamental importance of Thallium is the ability to accept electrons due to empty d-orbitals and thus establish additional bonds (σ bond and π bond) in chemistry. The Thallium metal, which has outer electronic configuration 6 s², 6 p1 shows oxidation states of Thallium (III) and Thallium (I). This research paper explains that Thallium (III) and Thallium (I) accepts lone pairs from various bi-dentate tetra-dentate Schiff base ligands due to p-orbital and vacant d-orbital. This research paper explains the Characterization, XPS and Toxicological Study of Or- ganothallium (III) Compounds with Schiff base ligands by physiochemical technique. X-Ray photoelectron spectrogra- phy (XPS) study of Thallium (III) complexes with Schiff Base ligands also reported in this paper. XPS study shows a single symmetrical peak without any splitting in photoelectron peak, which confirms diamagnetic nature of all prepared molecular adducts. All prepared complexes with Schiff base ligands show toxicological effect.