2-(4- Amino-3-subsituted and unsubsituted phenyl) imidazo and/or oxazolo )[4,5-b] pyridines la-h were diazotized to afford II. Coupling of the latter with diethylmalonate afforded llla,b while its coupling with malononitrile afforded VIa-d . the pyrazolo derivatives IVa-d, the pyrimido derivatives IVa-d were obtained when llla,b were cyclized with hydrazine, phenyl hydrazine , urea and thiourea respectively. The aminopyrazolo derivatives Vlla-d were obtained by cyclization of VIa-d with hydrazine. In addition a number of azo dyes were also synthesized. Another series of schiff,s bases were prepared from the reaction of Ia-h with different substituted benzaldhydes , then a novel series of cyclized compounds Xa-d and XIa-d were obtained by reaction of certain azomethine with chloroacetyl chloride and mercaptoacetic acid respectively. Molecular modeling and antimicrobial activity for some of the synthesized compounds were also involved.