Novel functionality in condensed matter physics is continuously attracting huge attention owing to the possible novel future applications including quantum computing, electronic devices and so on, leading to continuous discoveries of new materials and phenomena. This is part of these efforts in our research project to explore the novel functionality in quantum magnets. Here we propose to investigate a newly synthesized honeycomb antiferromagnet Co4Ta2O9 single crystals, whose magnetism is not reported yet, to fully understand the magnetism and its role in the magnetoelectric property via inelastic neutron scattering at LET, an ideal instrument for this project in terms of magnon energies based on our Xpress data of powder samples. Our study will provide new ideas for designing new functional magnetoelectric materials and applications.