AbstractSynthetic, structural and biological aspects of trigonal‐bipyramidal, Me2Si(NS)Cl and octahedral, Me2Si(NS)2types of organosilicon (IV) complexes of heterocyclic thiosemicarbazones (NSH) have been described. The complexes were characterized by elemental analysis, molecular weight determination, conductance measurements and electronic, infrared,1H and13C NMR spectral studies. Some ligands and their corresponding dimethylsilicon (IV) complexes have been tested for their effects on several pathogenic fungi and bacteria. Two representative complexes have also been found to act as sterilizing agents by reducing the production of sperm in male m