Allosteric hemoglobin (Hb) modifiers of hemoglobin which contain nitric oxide (NO) moieties allowing for the release of NO in vivo. The compounds retain the oxygen delivery capability of the allosteric hemoglobin modifier to bind Hb and enhance Hb's ability to deliver oxygen to cells and tissues, and also release NO from the NO moiety. Methods of delivering oxygen and/or NO to cells and tissues are also provided.