A small library of N,N-diethyl- and -diethanolsulfonamides of differently substituted 2-(2-pyridyl)- and 2-pyrazinyl-4-alkoxythiazoles has been synthesized and investigated in terms of their photophysical properties, electronic structure (quantum chemical calculations at the CAM-B3LYP/6-31+G(d,p) level of theory) and thin film morphology (Langmuir-Blodgett- and spin-cast films). By using the Langmuir-Blodgett technique we show how to exert direct control over the degree of aggregation in thin films made from different thiazole type dyes. In combination with spectroscopic investigations, we gained an in-depth understanding of the influence of aggregation on the electro-optical properties of thin films made of the here-investigated substances.