When developing aza-diarylethen 1 (Figure ) we strived for enhanced redshift of absorption, improving individual addressability of different isomers with light, and stabilizing the E isomeric metastable state. These improved properties were achieved through the introduction of a larger conjugated system and by enabling cross-conjugation at the stilbene fragment. The extended conjugated system also increased the stabilization of photochemically formed radicals to improve the photoinitiated polymerization of MA.