Short-wave infrared (SWIR) semiconductor materials are essential for the development of consumer optoelectronic applications such as telecommunication, sensing and biological imaging. Indium arsenide (InAs) quantum dot (QD) materials are not restricted and offer bandgap tunability throughout the whole SWIR, making them very promising for such applications. Active imaging applications such as sensing require both a SWIR source and a detector, for example a QD-light emitting diode (QLED) and a QD-photodetector (QDPD) respectively. However, because of the lack of high photoluminescence quantum yield (PLQY) InAs-based QDs, QLED development lags behind QDPD development. Strong advancements have been made for the synthesis of InAs/ZnSe core/shells to enhance PLQY of these materials in the SWIR.[1,2] However, further improvement is needed as efficiency rapidly declines with longer emission wavelengths and PL features remain broad. An appealing core/shell combination for emission at longer wavelengths is InAs/InP. InAs and InP have a common cation and a relatively small lattice mismatch, enabling the formation of a low-defect interface in core/shell structures. However, little work has been done on the development of these InAs/InP-based structures.[3,4] In this work we present work done on the In(As,P) alloy synthesis route published by Leemans et al.[5] Using amino-arsine and -phosphine for In(As,P) core synthesis gives a tunable method for particles with band-edge transition (BET) between 1150 - 1600 nm. Firstly, we present a synthesis method for In(As,P) with BET features between 1250 - 1650 nm, with FWHM as low as 90 meV. The synthesis has a chemical yield between 30 - 50 % and does not require any size-selective precipitation steps, making it more easily reproducible. However, the photoluminescence quantum yield (PLQY) of these core QDs remains low without surface treatment or shell growth (< 1%). Secondly, in this work we present a novel synthesis route for the growth of tetrahedral In(As,P)/InP core/shell structures. This synthesis enables In(As,P)/InP with variable thickness of 1 - 5 monolayers (ML) and core sizes used between 5 - 10 nm in edge length. The synthesis can be done in both 2- and 1-pot fashion. The BET is not broadened and PLQY is enhanced from << 1 % to roughly 1 %. Compared to the InAs/ZnSe materials, this is a relatively small increase. Through ab initio density functional theory calculations we can attribute this low PLQY to surface states on the InP shell. Finally, we present a synthesis route for facile ZnSe overgrowth of the In(As,P)/InP core/shell structure demonstrating luminescent materials with centre of emission between 1200 and 1550 nm. The material PLQY is between 12 - 16 % and the PL FWHM is typically between 120 and 90 meV. Again, this synthesis works both in a full 1-pot or a 2-pot fashion. These are record narrow PL features with relatively good PLQY for RoHS-compliant InAs-based QDs in the SWIR. They provide a strong material baseline for further development of QLED devices for consumer applications such as telecommunication, sensing and biological imaging.