Mendis has written several memorable songs for Sri Lankan films, most notably "Master Sir" for the film "Kalu Diya Dhahara" ("A column of black water"), where Neela Wickramasinghe performed it over the title sequence. "Master Sir" is about colonial Sri Lanka, narrating a story about the dignity of labour- a story about social justice. The song was recorded both in English (by Mendis and Sandra Edema) and Sinhala (by Neville Fernando; lyrics translated to Sinhala by Karunaratne Abeysekera). The song has remained a hit in Sri Lanka for over thirty years, mostly as a result of Neela Wickramasinghe's popularized version based on the musical arrangement of the English version (time signature, riffs etc.).