variety of heteroannulated chromeno[2,3-b]pyridines and their related compounds were efficiently synthesized from chemical transformations of 6-methylchromone-3-carbonitrile (1) with some cyclic and acyclic carbon nucleophiles. Also, the reactivity of carbonitrile 1 was studied towards 1-ethyl-4-hydroxy-3-nitroacetylquinolin-2(1H)-one (8) producing the unexpected 5-ethyl-10-methyl-8H-benzo[h]chromeno[2,3-b][1,6]naphthyridine-6(5H),8-dione (9). A diversity of 2-substituted-3-cyclohexyl-8-methyl-4H,6H-chromeno[3',2':5,6]pyrido[2,3-d]pyrimidine-4,6-diones were synthesized. Structures of the newly synthesized products have been deduced on the basis of elemental analysis and spectral data. The newly prepared compounds were screened for their antimicrobial activity.