“…Many applications have been identified, which include electrochromic device (ECD) [1,2], CD-R recording medium, solar cell [3], and gas sensing . The p-type semiconducting lead phthalocyanine (PbPc) was reported to be sensitive to many gases, such as NO 2 [4][5][6][7][8][9][10][11][12][13][14][15], NH 3 [6], Cl 2 [15][16][17], I 2 [17], O 2 [18], and H 2 [19]. Other p-type MPcs, such as CuPc and NiPc, were reported to be sensitive to both NO 2 [6,7,10,[21][22][23] and NO [24].…”