Aminocyclization of aldehydes to synthesize pyridine bases is an interesting reaction with HZSM-5 catalyst undergoing rapid deactivation. The catalyst characterization studies like NH3-TPD, XRD, TGA/DTA, Pore size distribution, SEM, CHNS, IR for the fresh and deactivated catalyst at various Si/Al ratio content as evidenced by the striking difference in the behavior of HZSM-5 catalyst in terms of its physicochemical characteristics, coke formation tendencies and higher selectivity to pyridine formation.