This study presents systematic theoretical investigations employing an ab initio DFT approach combined with analysis of heuristic tight-binding models. We examine the effect of using conjugated and non-conjugated bridge on the electrical transport of tetraphenyl-aza-BODIPY derivatives. This work demonstrates that, substitution a conjugated bridging atom by non-conjugated one, causes the electrical conductance to switch from constructive quantum interference CQI to destructive DQI (on/off). This demonstration of switching behaviour means that if molecules with alternating structures (i.e., non-/conjugated), can be deposited on a metal surface, then they form a basis for enhancing the thermovoltage in nanoscale thermoelectric nanotechnology devices.