General predictive rules for substitution of DTEs to achieve photo-induced electrocyclization capabilities would have great utility. The practical efficiency of photoswitching in DTEs is dependent on a number of parameters including forward and reverse photoreaction quantum yield and thermal stability of isomers. However, predicting whether electrocyclization is possible or not is an important first step that can be used to narrow the structural diversity and focus experimental studies on viable candidates. Further studies of quantum yield, photostability etc. can then be used to optimize practical systems for desired applications. To predict the thermodynamic (but not kinetic) feasibility of photocyclization, we use electronic structure calculations (see Supporting Information for details) to explore molecular structures with varying degrees of π-conjugation at the backbone and different side chains in the DTE moiety. We also focus our analysis on how specific chemical changes, such as oxidation of the sulfur atoms of the DTE unit or the introduction of electron withdrawing groups in the backbone, affect the photoswitching of these compounds. The chemical units that we explore in this work are representative of typical photoswitches that can be found in the literature. For simplicity and consistency, the studied (model) compounds are labeled as SG1-BB-SG2, to designate the backbone (BB) and side group (SG) moieties (Figure ). Previous theoretical works have investigated several aspects related to the design of DTE photoswitches as well as mechanistic details of the photoreaction. Here we follow a general approach by considering a large set of photoswitches and demonstrate that by simple inspection of the FMOs, their photo-induced electrocyclic capability can be readily predicted.