Convenient and simple procedures for the synthesis of phenazine and quinoxaline derivatives were developed via a reaction of ophenylenediamines and 1,2-dicarbonyl compounds. In addition, the synthesis of two new derivatives of 1,4-benzo diazine derivatives and the catalytic activity of magnesium sulfate heptahydrate (MgSO4?7H2O) in the room temperature condensation of o-phenylenediamines and 1,2- dicarbonyl compounds in ethanol as solvent are reported. This method has many appealing attributes, such as excellent yields, short reactions times, and simple work-up procedures.