| Index | Ligand Name | Structure | PDB code | Compound Potency nM |
| 1 | 35o | phosphodiesterase-9A in complex with inhibitor WYQ-C36D | 4qge | 0.5 |
| 2 | wtc | Human phosphodiesterase 9 in complex with inhibitor | 3jsi | 2.1 |
| 3 | 0wf | Human pde9 in complex with selective compound | 4g2j | 11 |
| 4 | 49d | Crystal structure of phosphodiesterase 9 in complex with (S)-C33 | 4y8c | 11 |
| 5 | luo | Crystal structure of the PDE9A catalytic domain in complex with inhibitor 28 | 4gh6 | 21 |
| 6 | pdb | Crystal structure of the PDE9A catalytic domain in complex with (R)-BAY73-6691 | 3k3e | 22 |
| 7 | 0wl | Human PDE9 in complex with selective compound | 4g2l | 32 |
| 8 | jar | Human PDE9 in complex with selective inhibitor | 3jsw | 66 |
| 9 | bye | Crystal structure of the PDE9A catalytic domain in complex with (S)-BAY73-6691 | 3k3h | 88 |
| 10 | ibm | Crystal structure of PDE9A(Q453E) in complex with IBMX | 3qi4 | 1.172e+005 |
| 11 | pdb | Crystal structure of PDE9A(Q453E) in complex with inhibitor BAY73-6691 | 3qi3 | 1.642e+005 |
| 12 | ibm | Crystal structure of PDE9 in complex with IBMX | 2hd1 | 5e+005 |