Table 1.

Experimental and calculated values of λ_max of thieno-thiazolostilbenes (cis-1a, trans: 1a, 2a, 3a, and 10a) and thienobenzo-thiazoles 1–5 along with main assignments obtained by calculations. The computational model (CPCM)TD-PBEh1PBE/6-31+G(d) (in acetonitrile) is employed, with geometries optimized at M06-2X/6-31G(d) level of theory. H and L denote the highest occupied and lowest unoccupied molecular orbital, respectively.

Molecule	λmax/nm (exp)	λmax/nm (calc)	Assignment
trans-2a	318	328	H → L
trans-3a	342	357	H → L
trans-10a	373	384	H → L
cis-1a	315	323	H → L
trans-1a	320	349	H → L
1	249	245	H − 1→ L H → L + 1
2	251	242	H − 1→ L H − 1→ L + 1
3	214	203	H − 1→ L + 4
4	213	204	H − 1→ L + 3
5	221	211	H − 1→ L + 2