4-O-methyl ether of resorcylic aldehyde has been condensed with (I) acetophenone, (II) ω: 4-dihydroxy acetophenone, (III) ω∶3∶4-triacetoxy-and (IV) ω∶3∶4∶5 tetra-acetoxy-acetophenone to form pyrilium salts. Their properties and reactions are described. The first compound which has no hydroxyl groups in it undergoes change into the corresponding chalkone when its solution is treated with sodium acetate or when largely diluted with water. The reverse reaction takes place also rapidly in acid solution. The other compounds resemble closely pelargonidin, cyanidin and delphinidin though they exhibit a comparatively marked poverty of colour in solutions.