A novel series of 7-(hetero) aryl substituted-pyrazolopyrimidines, prepared via an AlCl3 induced CC bond forming reaction of 7-chloro-5-phenyl-pyrazolo [1, 5-a] pyrimidine with arenes and heteroarenes have been investigated as PDE4 inhibitors. Among all the compounds tested the 7-indolyl substituted pyrazolopyrimidine showed good inhibition of PDE 4 in vitro.