Abstract: Supported metal nanoparticles have emerged as a new class of nanocatalyst. These catalysts showed not only high catalytic activity and simple separation of them using an external magnet but also a high degree of chemical stability in various organic solvents. Multicomponent reactions (MCRs) allow the assembly of complex molecules in one-pot and show a facile execution, high atom-economy and high selectivity, as afford good yields and are fundamentally different from two-component and stepwise reactions in several aspects. Quinazolines are reported to possess interesting pharmacological activities such as antihypertensive, antihistaminic, analgesic and anti-inflammatory, anticancer, and anti-HIV activities. Moreover, many naturally occurring and synthetic compounds containing the benzimidazole derivatives possess interesting pharmacological properties. In continuation of our interest in the application of new catalysts in MCRs, herein, an efficient one-pot synthesis of benzimidazolo-quinazolinone derivatives from readily available amine sources, aldehydes and dimedone under simple and convenient conditions. Nanoparticles supported on biopolymer as catalyst offers advantages including simplicity of operation, ecofriendly, easy workup, high yields of products and the recyclability of the catalyst.