Interest in atomically thin 2D materials skyrocketed with the isolation of graphene sheets from graphite parent crystals and the realisation that these sheets can be exploited in optoelectronic devices. The extraordinarily high charge carrier mobility in graphene of up to 200,000 cm 2 V -1 s -1 is a result of the changed electronic structure of the atomic layer when compared to the bulk material. The high mobility of semimetallic graphene comes at the price of an absent "off state" that has foreclosed its application in transistors. Strategies to open up graphene's bandgap revolve around the introduction of heteroatoms and structural defects in diffusion-limited or statistical post-processing as well as nanostructuring. However, none of these methods are scalable and they do not yield products able to compete with silicon based devices to date. Crystalline organic 2D materials that contain predictable "deletions" (i.e. pores) and heteroatoms by design are researched to make up for the missing bandgap of graphene. Most notably transition metal dichalcogenides, graphene derivatives and designer covalent organic frameworks (COFs) compete to be the next generation semiconductor. Graphitic carbon nitrides combine two important characteristics: (i) they are overall sp -hybridised and covalently bonded, and (ii) they consist of earth abundant, light elements (i.e. they are metal free). Poly(triazine imide) (PTI-MX) is a layered intercalation compound obtained from alkali halide salt melts and can be exfoliated to monolayers. Even though the material has high environmental stability, crystallinity, blue photoluminescence, and has found application as semiconductor in photo-and electrocatalyst, it has found little to no use in optoelectronic devices up to this point. In this work, (i) we elucidate the impact of different polycondensation conditions on the chemical makeup of PTI and its optical and electronic performance, (ii) we monitor the material quality at microscopic and macroscopic scales, (iii) we assemble photoconductor and organic light emitting diode (OLED) devices based on PTI, and (iv) we look at the effect of protonation on the electronic structure of PTI comparing results from theoretical calculations with observed optical spectra. The results of this study provide guidelines for improving the optical and electronic properties of organic layered materials; especially ones that incorporate triazine (C3N3) subunits.