New d-ribofuranoside derivatives containing two five membered heterocycles, isoxazole and triazole or two triazole rings, were synthesized. The final products as well as the synthetic precursors were physically and spectroscopically characterized. These new diheterocyclic derivatives together with other d-riboside compounds were assessed for their impact on PC3 cell line viability. We found that exposure of prostate cancer cells to some of these compounds caused a significant inhibition of cell growth and a G₀/G₁ cell cycle arrest, which was concomitant with alterations in the expression of proteins involved in cell cycle progression. Furthermore, the inhibitory activity was improved in di-heterocycles when the carbohydrate moiety was protected with a cyclopentylidene group compared to the isopropylidene analogues.