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Chromene heterocycles are reported to possess important activities such as antimicrobial,[1] anti-viral,[2] anti-inflammatory,[3] antimalarial,[4],[5] antiproliferative,[6] anti-tumor,[7] anti-cancer,[8] anti-estrogenic,[9] anti-helminthic,[10] and anticonvulsant properties.[11] They are useful as pigments and agrochemicals.[12],[13] In recent years, reagents for the preparation of these compounds have included Fe SB 3 sb O SB 4 sb /SiO SB 2- sb Met,[14] aminopropylated silica gel,[15] nano Ag/kaolin,[16] tetrabutylammonium fluoride (TBAF),[17] MgO,[18] Et SB 3 sb N in EtOH,[19] NH SB 4 sb Cl,[20] Fe SB 3 sb O SB 4 sb /PCL-PEG-PCL,[21] Fe SB 3 sb O SB 4 sb @SiO SB 2 sb ,[22] bmIm]Cl SP - sp ,[23] N,N-dimethylbenzylamine (DMBA),[24] saccharine-based ionic liquid [Bmim]Sac,[25] and amberlyst A.[26] Although all of these methods are effective, some of them have disadvantages. Tetrabutylammonium hydrogen sulfate (TBAHS) as a solid acid and phase transfer catalyst has recently been used in many organic reactions.[[27]] In the course of our study to develop new, green, and efficient methods for the synthesis of pharmaceutical heterocycles,[27],[30],[31] we now report an efficient and environmentally friendly method for the synthesis of 2-amino-5-oxo-5,6,7,8-tetrahydro-4H-chromenes from aldehydes, malononitrile, and dimedone using TBAHS ( I Scheme 1 i ). Next, we studied the generality and efficiency of this method by the reaction of various aromatic aldehydes with malononitrile and dimedone at 80 °C under solvent-free conditions ( I Table 7 i ). Furthermore, the efficiency of the catalyst is compared with some other catalysts in the synthesis of 4H-chromene derivatives ( I Table 8 i ). [Extracted from the article]