Microgrooves on self-assembled photonic-crystal (PC) films align liquid crystals (LCs) without any additional rubbing or surface treatment. Nematic (see Figure and inside cover) or twisted nematic LCs can be formed, depending on the relative orientation of the microgrooved films. A LC Fabry-Perot (FP) cavity was fabricated using these PC films, and electro-optic tuning of FP cavity modes is demonstrated.