This work includes preparing various heterocyclic compound types, which include the phthalazin, pyridazin, pyrazol, phthalazin-3,8-dione [5] and pyridazin-3,6-dione [6] derivatives which derived from hydrazide compound [3]. The structures of those compounds have been identified by the fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR) spectroscopy and checked with the use of the TLC technique, and evaluated the antibacterial activities for some of the synthesized compounds. Those activities have been characterized in vitro using the well diffusion approach against three types of the pathogenic strains of the bacteria Escherichia coli and Pseudomonas (G-) and S. aureus (G+). Results have shown that some of those compounds have shown good activity.