Background: Nucleon-pair correlations play an important role in low-lying states of atomic nuclei. Purpose: The aim is to study empirical proton-neutron interactions and investigate the contribution from spin-aligned proton-neutron pairs (with spin 9 and isospin 0) in low-lying states of 96Cd and 92Pd. Methods: The empirical proton-neutron interaction is obtained by using nuclear binding energies of a few neighboring nuclei and the nuclear shell model. The contribution from spin-aligned proton-neutron pairs in the shell model wave functions is evaluated by using the nucleon-pair approximation with isospin symmetry. Results: The empirical proton-neutron interaction is reasonably consistent with isoscalar interactions calculated by using the shell model. There exists an additional binding energy in both even-even and odd-odd nuclei originated from proton-neutron interactions. Spin-aligned isoscalar pairs play an important role in the 01+

 21+

 41+

 61+

  121+

  141+and 161+ states of 96Cd and the 01+

  21+states of 92Pd. For the  01+ and  21+ states

the conventional isovector SD pairs are more relevant. Conclusion: Both isoscalar and isovector nucleon pairs play an important role in low-lying states of N=Z nuclei. This is a consequence of nonorthogonality feature of nucleon-pair basis.Cited