A pyridine derivative exhibiting a photoelectric conversion is represented by formula (I)
1
wherein each of R
1
, R
2
, R
3
, R
4
is independently —OR′, —COOR′, —CONR′, —CHO, —CH
2
OR′, —CN, an alkyl group whose carbon number ranges from 1 to 20 inclusive, or —COONR′
4
, wherein R′ is a hydrogen, or an alkyl group whose carbon number ranges from 1 to 4 inclusive.