We demonstrate a scheme to use a Littman configuration external cavity diode laser (ECDL) as a stable-frequency light source to stabilize two cw single-mode Ti:sapphire lasers for laser cooling of magnesium fluoride molecules. An ECDL based on the Littman configuration is constructed and stabilized by a digital signal processor system. We stabilize the frequency of our ECDL to ±0.77MHz precision over 10 h and the Allan standard deviation reaches 2.6×10 11 at an integration time of 10 s. We lock two Ti:sapphire lasers through a transfer cavity, and either laser has a long-term frequency stability of ±2.5MHz.