A series of Pyridazine derivatives were synthesised by diazotization of substituted anilines followed by Friedel– Crafts acylation and coupling to form corresponding hydrazones which on Intramolecular cyclisation forms 3- acetyl- substituted benz pyridazine-4(1H)-one. Further, condensation reaction by treatment with hydrazine hydrate yields the expected 3’-methyl-substituted-pyrazolo [4, 3-C] Cinnoline derivatives.The synthesised compounds were characterized by analytical techniques like TLC, UV, IR, NMR Spectral studies. All the synthesised compounds were checked for drug likeliness using Molinspiration software and toxicity prediction studies were conducted using Protox and Gusar softwares and found to be efficacious and Screening for anti-microbial activity studies. All the synthesised analogues showed good anti-fungal activity against various pathogenic bacteria and fungi.The compound PZ-5 was found to be safe and moderate drug in comparison to standard drug.