Abstract: The present disclosure provides cytidine derivative dimers, salts and compositions of the cytidine derivative dimers, and methods of making and using the cytidine derivative dimers that are useful for treating a neoplasm in mammalian subjects. A cytidine derivative dimer may have the following general formula (I): By molecularly designing such cytidine-based compounds, the disclosed cytidine-based derivative dimers/salts show significant inhibiting effects on HCT-116 human colon cancer cells, and exhibit strong growth inhibiting effects on HCT-116 human colon cancer xenografts grown in nude mice. The disclosed cytidine derivative dimers/salts provide high anti-tumor activity with low toxicity and are useful for treating cancers.