This work reports the use of monolayer colloidal crystal of polystyrene spheres as a template combined with electroless deposition to fabricate Ag through-sphere segment void (SSV) arrays. Experimental and theoretical (finite-difference time-domain) results reveal that the structured Ag through-SSV arrays create extraordinary optical transmission (EOT) and largely enhanced localized fields, thereby enabling EOT-based plasmonic sensing with a sensitivity of 295.38nm/RIU (RIU=refractive index unit) and reproducible enhanced Raman signal with an enhancement factor of about 104, respectively. These results suggest a low cost, feasible way to integrate plasmonic sensing and molecule-specified Raman detection on a single biochip.