<jats:title>Abstract</jats:title><jats:p><jats:boxed-text content-type="graphic" position="anchor"><jats:graphic xmlns:xlink="http://www.w3.org/1999/xlink" mimetype="image/gif" position="anchor" specific-use="enlarged-web-image" xlink:href="graphic/mcontent.gif"><jats:alt-text>magnified image</jats:alt-text></jats:graphic></jats:boxed-text><jats:p>Two new solanapyrone analogues, solanapyrones N and O (<jats:bold>1</jats:bold> and <jats:bold>2</jats:bold>, resp.), and three known compounds, solanapyrone C (<jats:bold>3</jats:bold>), nigrosporalactone (<jats:bold>4</jats:bold>), and phomalactone (<jats:bold>5</jats:bold>), were isolated from the fermentation culture of <jats:italic>Nigrospora</jats:italic> sp. YB‐141, an endophytic fungus isolated from <jats:italic>Azadirachta indica</jats:italic> <jats:sc>A. Juss</jats:sc>. The structures of the new compounds were elucidated on the basis of spectroscopic analysis. The antifungal activities of <jats:bold>1</jats:bold>–<jats:bold>5</jats:bold> towards seven phytopathogenic fungi were tested. Most of the compounds exhibited no or only weak antifungal activities.