Described are photochromic materials of indeno [2',3':3,4]naphtho[1,2-b]pyran structure, characterized in that they have a nitrogen or sulfur containing substituent at the 11-position ring atom, are substantially free of spiro-substituents at the 13-position and have been adapted to provide an increase in the sensitivity, visible lambda max or a combination thereof as measured in the Indenonaphthopyran Photochromic Performance Test. Optional substituents can be present at the other positions of the indeno [2',3':3,4]naphtho [1,2-b]pyran structure. Also described are naphthols used to produce the photochromic materials and photochromic articles that contain or that have coatings containing at least one of the novel photochromic materials or combinations thereof with other photochromic materials.