Boron suboxide (BOx, x< 1.5) is a promising material for a wide range of applications. The elastic modulus (E) of 473 GPa has been reported for crystalline BO0.17, which tends to exhibit ultra-low friction as a direct consequence of boric acid (H3BO3) formation. When thin films are formed, they are reported to be amorphous with E<300 GPa. The objective of this work was to understand the formation of crystalline BOx based films. The methodology applied was to study the correlation between composition, structure, and properties of this material with experimental and theoretical means. The growth technique used was reactive RF magnetron sputtering in an Ar/O2 ambient and the characterization included a wide range of analytical techniques. The theoretical tools employed were classical molecular dynamics and ab initio calculations. Two distinctive approaches were used to find a pathway for crystalline film synthesis: firstly extensive ion bombardment during film growth and secondly control of chemical composition as well as quantum design. When films were bombarded with Ar+ ions, they remained amorphous and E (55-248 GPa) was found to be a strong function of film density (p=1.5-2.3 g/cm3) at constant chemical composition. On the other hand, when the chemical composition was varied, the behavior of E was more complex. Firstly, it was established that the role of O in amorphous films is different than in crystalline BO0.17, where O shortens the chemical bonds. As x in BOx increased from 0.08 to 0.60, the fraction of long B-O bonds increased resulting in E decreasing from 273 to 15 GPa. Secondly, H incorporation (up to 4.7 at.%) reduced E, most likely due to a H3BO3 formation. Thirdly, C incorporation (up to 0.6 at.%) shortened the average bond length, increasing p and E, but decreasing the relative dielectric constant (19.2-0.9). Based on ab initio calculations investigating the effect of alloying metals with BO0.17, the formation of a crystalline Y containing phase was predicted. This so-called BOY phase was calculated to be 0.36 eV/atom more stable than BO0.17 and B-B were 4.9% shorter. Experimentally, this phase was synthesized and properties were determined. The measured E of 316 GPa was consistent with the prediction based on elastic constants. Moreover, the BOY phase was found to be thermally stable at temperatures up to 1000 °C and exhibited a resistivity of 3.8 Ωcm.