This book is written on the research work done on organotellurium compounds as organotellurium compounds in recent years have attracted considerable interest in the field of organic synthesis, ligand chemistry, organic superconductors, photoimaging agents and semiconductors. Organyltellurium trihalides constitute an important class of organic derivatives of tellurium and exhibit a variety of reactions. Lewis acid' or acceptor behaviour is one such property and a few organyltellurim trihalides have been investigated for this behaviour 4 Hydroxyphenyltellurium trichloride is the only hydroxyaryltellurium trihalide, whose complexes with a few donor bases have been identified. Such complexes of organotellurium trihalides are also known to possess considerable antimicrobial activity. The present work has, therefore, been undertaken with a view to prepare the complexes of hydroxyaryltellurium trihalides with some nitrogen, oxygen and sulphur donor bases, and characterize them in solution as well as in the solid state using various physicochemical techniques.