Biginelli, an important multicomponent reaction provides an avenue for the synthesis of different biologically active heterocyclic compounds. During the past decade, one pot multicomponent reactions have attracted the attention of organic and medicinal chemists due to high atom economy, time and enery saving convergent nature. The present manuscript reports a simple one pot three component synthesis of 3, 4-dihydroprimidin-2(1H)-thiones from various diversely substituted aldehydes, ethyl acetoacetate and thiourea using a orange peel powder as a natural catalyst on ultrasonic irradiation in aqueous medium as the solvent. The advantages of this reaction are less reaction time, high yield, easy availability of the catalyst and green nature.