Mn(III)–pentadentate Schiff base complex supported on multi‐walled carbon nanotubes as a recyclable and reusable, green and nano‐heterogeneous catalyst was designed and fully characterized using infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, inductively coupled plasma mass spectrometry, elemental analysis and thermogravimetric analysis. A facile, eco‐friendly, mild and green procedure was developed for the one‐pot three‐component synthesis of tetrahydrobenzo[b]pyrans via tandem Knoevenagel–Michael cyclocondensation reactions between aromatic aldehydes, 1,3‐diones and malononitrile using a catalytic amount of Mn(III)–pentadentate Schiff base complex supported on MWCNTs as an efficient recyclable heterogeneous catalyst under solvent‐free conditions at room temperature. This process has the advantages of easy availability, stability, recyclability and eco‐friendliness of the catalyst, short reaction times, high to excellent yields and simple work‐up procedure.
