The research work has been divided into three parts, Part I, Part II, and Part III. Part I A Series of di-and tri-organotin(IV) complexes (23) have been synthesized by the reaction of tri- and diorganotin(IV) chlorides/oxides with 3(3-Indolyl)-propionic acid and 4,5-diphenyl 2-imidazole thiol ligand in dry toluene under reflux condition for 6-8 hrs. The coordination behaviour of ligands and geometry of synthesized complexes were studied by employing different analytical techniques such as FTIR, multinuclear NMR (1H, 13C, 119Sn). Based on these results, the ligand appeared to coordinate the Sn atom via COO- & -SH moiety. The triorganotin(IV) derivatives reveal a monomeric tetrahedral structure in solution. While diorganotin(IV) dicarboxylates have shown an octahedral geometry, however, the coordination around Sn change from six to five in solution, in most cases. The appearance of new peaks for Sn-O and Sn-S in the IR spectra indicated the formation of organotin(IV) carboxylates and values point to the bidentate nature of ligands in solid state. Multinuclear NMR (1H, 13C and 119Sn) data revealed that the coordination number of Sn changed from five to four in triorganotin (IV) derivatives and from six to five in diorganotin(IV) compounds. Part II For the first time, we have studied Electrogenerated chemiluminescence of Ru(phen)32+ /Dibutylamino)ethanol system. ECL of Ru(phen)32+ /DBAE was compared with ECL of Ru(bpy)32+ /DBAE at both Au and GC electrodes. ECL intensities of Ru(phen)32+ /DBAE were found several times of ECL of Ru(bpy)32+ /DBAE. In addition, Ru(phen)32+ is sensitively detected using very low concentration of DBAE. ECL behavior of Ru(bpy)32+ /DBAE and Ru(phen)32+ /DBAE was vigilantly studied under cyclic voltametry and amperometry conditions at Au and GC electrode.Therefore, Ru(phen)32+ / DBAE system is promising for the sensitive detection of biologically important compounds. Part III We have presented a new, easy and environment friendly method for the facile aqueous preparation of silver nanoparticles well defined in size and shape by exploiting EG as mild reductant. No additives, such as surfactant is needed in the procedure. The size and shape of the silver nanoparticles are sensitive to the reactant temperatures and the concentration of the precursor. A denser concentration of precursor facilitates the formation of large and highly crystalline nano-Ag particles. The other metal nanoparticles, such as gold, can be successfully fabricated as well by this technique. It is important to note that the reducing reactivity of EG was rapidly increased with the increase in reaction time, concentration of the precursor and temperature, which offers the possibility of preparation of metal nanoparticles with a shift of particle size range from ca. 10 to 30 nm. In addition, Quantum dots (QDs) are reported as promising fluorescent probes for biomedical imaging. We have tried to fabricate CdTe QDs using SFSD as reducing agent under isothermal method.