Dicoumarol (3) obtained from 4-hydroxy coumarin (2) through different routs has been found pharmacologically active and responsible for anticoagulant properties. Mechanistically interesting 2-nitroso-2-methyl-1,3-indandione dimer (11) has been synthesized by the nitration of 2-methyl-1,3-indandione (9) when the reaction is carried out at 00C. In a patent work phthalimide derivatives (13) synthesized from the reaction of phthalimide with hydrazones have been found to be potent insecticides. Phthalimide esters of the type (14) have also been synthesized and evaluated as potential prodrugs. In a substitution reaction 1H –isoindole-1,3-(2H) dione (12) replaces chloride from chloroacetonitrile to yield N-cyanomethyl phthalimide (15).