If your organic crystals not showing SHG efficiency you can go for third harmonic generation (THG) measurement. if possible put dopent and increase efficiency of in your parent materials.
Thank you for your valuable suggestions. Where is Third Harmonic Generation studies available? My crystals are needle shaped so, is it possible to take THG measurements Sir?
THG measurement is availble on Trichy NIT, you should need crystals with a prismatic faces. If you have needle shape means it is difficult to handle and taking measurements is not possible. better you try to grow same crystals with a prismatic faces while changing parameters.