In family 3, when comparing conjugates presenting the same nucleobase, cytosine derivatives 21 and 25 exhibited the most striking differences in T. gondii β-gal activity. While 21 almost abolished parasite proliferation when applied at 0.1 µM (4%), 25 exerted reduced antiparasitic efficacy even at 1 µM (35%). This indicates that the nature of the linking between the diruthenium scaffold and as well as the nucleobase can strongly influence the activity of the conjugates.