Mun Sen was transferred to the Penang branch of the bookshop he was working at in Singapore. In Penang, the bookshop was located on Carnarvon Street. Penang was where he would settle down for the rest of his life. In the 1955 Poay Cheng Building School Fund catalogue, it is recorded that Rui Ting 瑞廷書局's Penang branch had a shortage of staff, and Mun Sen was asked to head up to Penang to help out. He continued painting when he had free time and consigned his paintings for sale on commission at a frame-making shop. In a short time, he became close to an arts patron of Hokkien-descent called Ooi Hwa 黃花 and subsequently received financial support from to set up a gallery together. A 1953 interview records that the Penang branch of the bookstore was called Tong Wen 同文書局 on Beach Street. In addition, the interview also mentions that he received the help of Ong Seng Rong 王森榮 in setting up his 美術館 art gallery and also his photo studio business.

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1972. Pameran Peringatan Yong Mun Sen/ Yong Mun Sen Memorial Exhibition. Exhibition catalogue 17 March - 4 April. Kuala Lumpur: Balai Seni Lukis Negara/National Art Gallery; 金戈 Jing Ge，1955。’楊曼生傳 (Biography of Yong Mun Sen)‘ Poay Cheng Building School Fund Exhibition Catalogue, 4; 楊曼生先生從藝四十年. 南洋商报, 3 August 1953, Page 10