Formation of derivatives of PQQ and PQQ‐Triester for the Detection of PQQPQQ is an organic redox/cofactor found in a class of enzymes called quinoproteins. It has been reported that materials like milk, egg yolk, vinegar, beer, serum, urine, and biological tissues contain little amounts of PQQ. To facilitate studies on PQQ, a simple detection of PQQ could be extremely useful. For this purpose, we describe in this paper some adducts of PQQ or PQQ‐triester with 1,2‐diamines, 2,4‐dihydroxyaniline, pyrrole, indole as well as an oxidation product of PQQ. UV and fluorimetric detections of these colored products show that this method is relatively sensitive. The reaction of PQQ‐triester with (MeO)3P to the phosphole adduct 13 is of great importance: the use of [32P]‐labeled trialkyl phosphites will make this reaction an extremely sensitive method to detect PQQ.