Abstarct: Heterocyclic compounds are one of the largest and most diverse families of organic compounds. Nitrogen containing heterocycles play a fundamental role in biological processes, pharmaceutical industry, material science and natural products. In this research work, some nitrogen heterocycles were synthesized via carbon-carbon and carbon-nitrogen coupling reactions in the presence of the palladium catalyst, copper(II) salen complex and a new heterogeneous catalyst baxsed on poly(vinyl choloride) as follow: 1. One-pot synthesis of a new derivatives of 2-alkanol-substituted pyrrolo[2,3-b]quinoxalines from N-alkyl-3-chloroquinoxaline-2-amines and propargylic alcohols through Sonogashira coupling reaction. 2. Multi-component copper-free synthesis of new 1-alkyl-2-(aryloxy)methyl-1H-pyrrolo[2,3-b]quinoxalines from phenol or naphthol derivatives, propargyl bromide and N-alkyl-3-chloroquinoxaline-2-amines catalyzed by palladium catalyst. 3. A novel rout for the copper-free synthesis of 4-methyl-1-(1H-pyrrolo[2,3-b]-quinoxalin-2-yl)cyclohexanols and 2-phenyl-1-(1H-pyrrolo[2,3-b]quinoxalin-2-yl)propan-1- ols from N-alkyl(aryl)-3-chloroquinoxaline-2-amines with calcium carbide and cyclohexanones or 2-phenylpropanal catalyzed by palladium catalyst. 4. Synthesis of a new derivatives of 1,2,3-triazole-lixnked quinoxaline scaffold from 3-propynlthioquinoxaline with aromatic azides using copper(II) salen complex click reactions in aqueous ethanol. 5. Using PVC-supported triazole-copper(II) complex as a new heterogeneous catalyst for the synthesis of 1,2,3-triazoles through click reactions. The structures of all the synthesized compounds were confirmed by the spectroscopic data. A number of synthesized compounds were evaluated for anti-bacterial activities.