In this paper, we describe the synthesis and characterization of iridium (III) half sandwich complexes of stoichiometry [Cp+IrCl2L] with Cp = 5-C5 EtMe4; L = alanine anhydride (I), ortho- (II) and para-aminophenol (III). For comparative purposes, the ionic complex [Cp*IrCl(o-phen)](PF6); Cp* = (5-C5Me5) (IV) has been also synthesized and characterized. All the isolated complexes have been characterised by C, H and N elemental analysis; infrared and 1H nuclear magnetic resonance spectroscopies; 1H-1H COSY; mass spectrometry (ESI/TOF), thermogravimetry and, in the case of (IV), by conductivity measurements. The cytotoxic behaviour of the isolated complexes was studied against HeLa and complexes (III) and (IV) were found to have an IC50 close to 160-170 m, quite close to the IC50 value of cisplatin which was found to be 134,7 m, indicating that they are good cytotoxic agents. However, complexes (I) and (II) showed IC50 values above 250 m indicating their low cytotoxicity.