In this research, our synthetic targets are Zn(II) porphyrin – Co(III) heterodinuclear systems, which can be explored as photoactivated cytotoxins in chemotherapy. Initially, in Chapter 2, we have synthesised the main Zn(II) porphyrin based electron donor components [Zn(tpp-NH2)] 2.05 and [Zn{(tpp-NH2)4}] 2.08 while optimising literature-reported methods. We have optimised methods to obtain the best yield while reducing the chemical cost and solvent usage. Specifically, [Zn(tpp-NH2)] 2.05 was of interest to us to elaborate and use as a donor component in the targeted Zn(II)-Co(III) heterodinuclear complexes. The majority of work focused on designing and synthesising elaborated Zn(II) porphyrin electron donor components. Chapter 3 describes the development and use of reductive amination reactions to elaborate [Zn(tpp-NH2)] 2.05. From this study, we have been able to synthesise four new zinc porphyrin complexes ([Zn(L1)], [Zn(L2)], [Zn(L3)], [Zn(L4)]) with the different bidentate or tridentate second metal binding site. Chapter 4 describes the construction of a second metal binding site on the amine group of Zn(tpp-NH2) using amide coupling reactions. From the Chapter 4 study, we have been able to synthesise one new zinc porphyrin complex ([Zn(L7)]) and two more literature-reported zinc porphyrins ([Zn(L6)] and [Zn (L8)]) while optimising literature methods. Chapter 5 explores the Co(III) complexation ability of those elaborated Zn(II) porphyrin-based electron donor components using cobalt(III) triflate (en, tren and dien) complexes. In this Chapter, we provide evidence for the formation of Zn(II) porphyrin – Co(III) heterodinuclear complexes by reacting [Zn(L1)] and [Co(en)2(OTf)2]OTf and then the photoactivated ligand release upon light exposure. Moreover, the formation of a heterodinuclear complex between [Zn(L8)] and [Co(dien)(OTf)3] was also promising based on the NMR spectroscopy and mass spectrometry evidence. In Chapter 6, we attempted to synthesise cytotoxic Co(III) nitrogen mustard complexes with labile ligands such as triflate (OTf) and nitrile (NCCH3). Specifically, in this Chapter, we have experimented with the synthesis of [Co(ceen)2(OTf)2]OTf (6.04) and [Co(ceen)2(NCCH3)2]OTf3 (6.05). Based on the mass spectrometry, we have synthesised [Co(ceen)2(OTf)2]OTf (6.04), but unfortunately, we could not isolate it in a pure form. Then we explored the nitrilium chemistry in order to synthesise alternative [Co(ceen)2(NCCH3)2]OTf3 (6.05) complex. Even though we have not yet been able to synthesise the targeted [Co(ceen)2(NCCH3)2]OTf3 (6.05) complex, we were able to isolate new complex, [Co(ceen)2(NCCH3)(NO2)]OTf2 (6.14). Based on the results, the use of nitrilium chemistry is promising for the synthesis of the targeted [Co(ceen)2(NCCH3)2]OTf3 (6.05) complex, but further optimisations are required Our study provides a synthetic strategy that can be used to synthesise and study a diverse range of Zn(II) porphyrin – Co(III) heterodinuclear systems. Moreover, the preparation of two upcoming publications is ongoing– one addressing the photoactivated ligand release in a Zn(II) porphyrin – Co(III) heterodinuclear system and the other involving new Co(III) nitrogen mustard-nitrile complexes.