Microwave-assisted synthesis of calix [4] resorcinarenes by cyclocondensation of various aldehydes and resorcinol catalysed by 12-tungstophosphoric acid type Keggin (H3PW12O40· 13H2O) or concentrated HCl is described. Excellent isolated yields (up to 90%) were attained within short reaction times (typically, 3–5min) when the reaction was performed under microwaves irradiation.
