Some 6-Phenyl/Biphenyl-4-yl-2-[2-(pyridin-2-ylamino)-ethyl]/-2-(2N-subtituted amin-1-yl)-ethyl-4,5-dihydropyridazin-3(2H)-one (4a-h) were synthesized by reacting 6-phenyl/biphenyl-4,5-dihydropyridazin-3(2H)-one with bromoethyl derivatives of cyclic secondary amines and 2-aminopyridine. All the compounds, 4a-h, were evaluated as anticonvulsant by using maximum electro shock (MES) and isoniazid (INH) induced convulsion methods at 50mg/kg dose level, and as antitubercular by Microplate Almar Blue Assay (MABA) method. In anticonvulsant activity, phenytoin (25mg/kg) and sodium vaproate (50mg/kg) were used as reference drugs. All compounds (4a-h) showed significant anticonvulsant activities against both MES and INH methods, and compound g showed highest activity against MES method. In antitubercular activity, compounds 4c-4h showed 25 μg/ml MIC value, and compounds 4a-4b exhibited 50 μg/ml MIC value when compared with reference drugs [isoniazid (3.125 μg/ml), pyrizinamide (3.125μg/ml)] and (streptomycin 6.25μg/ml) MIC values, and found less potent than the reference drugs.