A simple D − A (donor − acceptor) type receptor ((2E, 2′E)-3, 3′-(10-octyl-10H-phenothiazine-3,7-diyl)bis(2-(benzo[d]thiazol-2-yl)acrylonitrile)) (PBTA) containing nitrile-vinyl linkage was designed and completely characterized. The receptor PBTA detects CN− ions based on “turn-off” effect with admirable spectral properties. It also owns some of the merits like “naked-eye” color change, ultrafast response (90 s), lowest detection limit (1.25 × 10-10 M) as well as quantitation limit (4.17 × 10-10 M) with the pH range 4–11 which is more suitable pH to make use of the receptor PBTA in physiological medium. The instant detecting ability of the receptor over CN− ions was proved using paper test strip and cotton balls. Further, the utilization of the receptor PBTA was also extended to track CN− ions in realistic samples (water and food samples) and in HeLa cells bioimaging.