This thesis comprises the targeted synthesis and characterization of trinuclear transition metal complexes of C3 symmetric ligands. Furthermore the defined linkage of the trinuclear subunits into higher aggregates as well as coordination polymers was presented utilizing different step-by-step synthetic strategies. The complexes were characterized with respect to their magnetic properties. Three different types of bridging ligands based on phloroglucinol, triaminobenzene and triaminoguanidine were utilized. New C3 symmetric ligands were introduced. A directed access to strongly ferromagnetic coupled high-spin compounds utilizing the spin polarization effect as well as antiferromagnetic coupled triangular compounds with a resulting S = 1/2 ground state was pointed out. Some of these compounds possess intriguing magnetic properties for later applications.