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In the present work the synthesis of various 4-aryl-2-(coumarin-3-yl)-6-(4-methyl-3-phenyl coumarin-6-yl)pyridines (6a-i) and 4-aryl-2-(coumarin-3-yl)-6-(4-methyl-7-methoxy coumarin-8-yl)pyridines (7a-i) have been carried out by reacting 1-[2(H)-1-benzopyran-3-yl]-3-aryl-prop-2-en-1-ones (coumarinoyl chalcones) (3a-f) with appropriate coumarinoyl methyl pyridinium bromide salt 4 and 5 respectively. The target compounds were characterized by the IR, 1 H-NMR, 13 C-APT and mass spectral analysis. Preliminary examination of target compounds as antimicrobial agents has been carried out using Broth dilution method.

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In search for new antimicrobial agents a series of new modified pyridine and bipyridine substituted coumarins 5a-y was designed and synthesized by adopting molecular hybridization strategy. All the synthesized compounds were evaluated for their in vitro antimicrobial activity using broth dilution method against selected bacterial (Gram-positive and Gram-negative) and fungal strains. Compounds 5a, 5f, 5g, 5n, 5r, 5t, 5w, 5x and 5y demonstrated promising antibacterial activity while other derivatives showed comparable activity to standard drugs used as reference.

A convenient and efficient strategy has been devised for the synthesis of bipyrido‐fused coumarins employing Kröhnke's pyridine synthesis approach. In the present work, 4‐hydroxycoumarins 1a–d were reacted with appropriate chalcones 2a–c to afford desired bipyridyl‐fused coumarins 3a–l. The structures of all the newly synthesized compounds 3a–l were ascertained by IR, 1H NMR, 13C NMR, mass spectral data, and elemental analyses. The compounds were further evaluated for their antimicrobial response against representative panel of pathogens, and the results thus obtained were compared with those of standard drugs. Few of the derivatives 3c, 3f, and 3i exhibited promising potency.