Pyran derivatives represented by any of chemical formulae (1) to (3). They are highly sensitive to visible light and highly luminescent and hence are useful in various applications in photochemical polymerization, organic electroluminescence, and dye lasers. In chemical formulae (1) to (3), R1 and R2 each independently represents hydrogen, alkyl, alkenyl, or aryl (the alkyl and aryl may be substituted); R3 represents cyano, carboxyl, a carboxylic ester group, amido, or a five- or six-membered heterocycle optionally forming a fused ring; and R4 represents hydrogen, halogeno, cyano, carbonyl, or a substituent derived from carbonyl, provided that R1 and/or R2 may form a cyclic structure in cooperation with the benzene ring bonded thereto.