The invention provides novel nucleosides and related processes, pharmaceutical compositions, and methods. The novel nucleosides are useful in a wide variety of antiviral, antineoplastic, and antibacterial applications. Preferred embodiments of the instant invention include novel 2 halogen-substituted, 3 halogen-substituted, and 2,3dihalogen-substituted analogues of 3-deazaadenosine, and novel 3 halogen-substituted analogues of 3-deazaguanosine. Compounds of the instant invention, including 4-Amino-6-fluoro-1-(-D-ribofuranosyl)imidazo[4,5-c]pyridine and 6-Amino-7-bromo-1,5-dihydro-1--D-ribofuranosylimidazo[4,5-c]pyridin-4-one, have exhibited potent antiviral and anticancer activity in vitro. The compounds are also useful in the concomitant treatment of bacterial infections associated with viral infections such as AIDS.