The design, synthesis, and biological evaluation of a series of pyrazolopyridines was carried out. Structural optimization of the aniline moiety of 4-anilinopyrazolopyridine derivative 3a, which is one of the newly discovered chemical leads for PDE4 inhibitors from our in-house library, was performed successfully. The details of the discovery of new orally active PDE4 inhibitors, which are expected to show therapeutic potential, are presented and their structure-activity relationships are discussed. Pharmacological evaluation and pharmacokinetic data for representative compounds are also presented.