Starch sulfate as bio-supported solid acid catalyst was applied to synthesis of heterocyclic compounds such as 2,3-dihydroquinazolin-4(1H)-one, 2-substituted-1,2,3,4-tetrahydro-4-quinazolinones, 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-one, 1,8-dioxo-octahydroxanthenes, and 5H-dibenzo[b,i]xanthene-5,7,12,14(13H)-tetraone derivatives under thermal solvent-free conditions. In all these synthetic methods, the work-up is simple and the catalyst can be easily separated from the product and reused for several times without any loss of its activity. The present protocol with starch sulfate as an effective catalyst is convincingly superior to the recently reported catalytic methods with respect to reaction times and yields of the obtained products.