Uses of pyrrolopyrimidines with anti-Mer tyrosine kinase activity as anti-infective agents, immunostimulatory and immunomodulatory agents, anti-cancer agents (including against MerTK−/− tumors and ITD and TKD mutant forms of Acute Myeloid Leukemia (AML)), and as adjunctive agents in combination with chemotherapeutic, radiation or other standard of care for neoplasms.