Synthesis of a series of novel pyrroloquinolinone and pyrroloquinoline derivatives has been accomplished by intramolecular domino Knoevenagel hetero Diels-Alder reaction and intramolecular imino Diels-Alder reaction. These compounds were evaluated for their antibacterial activity against bacterial pathogens using disc diffusion and broth dilution methods. The efficacy of binding of these compounds to gyrase, an enzyme known to play a key role in bacterial replication is examined by studying its supercoiling and relaxation and also its gene expression using PCR method. The results indicated that most of the synthesised compounds exhibited good antibacterial activity against the microorganisms with MIC values of 5mM and could inhibit gyrase effectively leading to cell death.