&lt;strong&gt; &lt;/strong&gt;&lt;strong&gt; &lt;/strong&gt;&#x0D; &lt;strong&gt;Triethyl ammonium sulphate catalyst&lt;/strong&gt;&lt;strong&gt;&lt;/strong&gt;&lt;strong&gt; one pot, Solvent free synthesis of novel Coumarin derivatives as antimicrobial agents.&lt;/strong&gt;