Abstract1,3,8,10,12‐Pentazanaphthacene‐2,4,7,9(12H,3H,8H,10H)‐tetraones (linear pyrimidine‐fused 5‐deazaflavins) and 1,3,6,8,12‐pentazabenz[a]anthracene‐2,4,7,9(12H,3H,6H,8H)‐tetraones (bent pyrimidine‐fused 5‐deazaflavins) were synthesized by condensation of 7‐alkylaminoquinazoline with 6‐chloro‐5‐formyl‐3‐methyluracil. Also, their flavin analogs, 1,3,5,8,10,12‐hexazanaphthacene‐2,4,7,9(12H,3H,8H,10H)‐tetraones (linear pyrimidine‐fused flavins) and l,3,5,6,8,12‐hexazabenz[a]anthracene‐2,4,7,9(12H,3H,6H,8H)‐tetraones (bent pyrimidine‐fused flavins) were synthesized by cyclization of 7‐[N‐alkyl‐N‐(5‐nitrou