A one-step synthesis of a new series of spiro-pyrazolines has been accomplished by the 1, 3- dipolar cycloaddition of 1, 3-diphenylnitrilimine with various fulvenes (2, 3, 4, 5-tetraphenyl fulvene (1) and its analogues (2, 3), 9-benzalfluorene (7) and its analogues (8, 9) and 6, 6- diphenylfluvene (13)). With the exception of 13 all other fulvenes undergo 1, 3-dipolar cycloaddition across the exocyclic double bond to give the hitherto unreported spiro- ...