New biocidal compounds were synthesized by reacting 4-hydroxy acetophenone with ethyl cyanoacetate and 2-chlorobenzaldehydes and ammonium acetate in absolute ethanol to give 4-(2-chlorophenyl)-2-hydroxy-6-(4-hydroxyphenyl) nicotinonitrile which by epoxidation gives 4-(2-chlorophenyl)-6-(4-(oxiran-2-ylmethoxy) phenyl)-2-oxo-1,2-dihydropyridine-3-carbonitrile. Another compound was synthesized by reacting 4-hydroxy acetophenone with ethyl cyanoacetate and 4-nitrobenzaldehydes and ammonium acetate in absolute ethanol to give 2-hydroxy-6-(4-hydroxyphenyl)-4-(4-nitrophenyl)nicotinonitrile witch by epoxidation gives 4-(4-nitrophenyl)-6-(4-(oxiran-2-ylmethoxy) phenyl)-2-oxo-1,2-dihydropyridine-3-carbonitrile. The synthesized four compounds and standard biocide (Zn omadine) were added separately to LDPE and HDPE and polystyrene in the same ratio (0.1 phr) followed by studying the melt flow rate and mechanical properties and electrical properties of LDPE and HDPE and polystyrene. In addition the biological activity of the prepared blends with LDPE or HDPE or PS were studied against two local isolates E. coli sero type O145 as gram-negative bacteria and S. epidermidis as gram-positive bacteria The antimicrobial test was performed quantitatively using the standard test method .