Isocyanurate containing periodic mesoporous organosilicas (ICS-PMO) without any post-modification was used as a novel heterogeneous catalyst for synthesis of tetrahydrobenzo[b]pyran derivatives via one‐pot three‐component condensation of aromatic aldehydes with malononitrile (or ethyl cyanoacetate) and dimedone. The catalyst was characterized by FT-IR Spectroscopy, TEM, SEM and BET techniques. Products were obtained in short reaction times with excellent yields in water under reflux conditions. The catalyst could be recycled and reused for several times without noticeably decreasing the catalytic activity.